APPENDIX E. NOISE AND VIBRATION TECHNICAL REPORT

APPENDIX E. NOISE AND VIBRATION TECHNICAL REPORT

Environmental Assessment May 2016 South Central Light Rail Extension

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Environmental Assessment May 2016 South Central Light Rail Extension


Noise and Vibration Technical Report March 2016 Environmental Assessment South Central Light Rail Extension

EXECUTIVE SUMMARY

This technical report documents the findings of potential noise and vibration impacts for the proposed South Central Light Rail Extension Project in Phoenix, Arizona. The technical report and findings are in support of the Environmental Assessment (EA). The 5-mile proposed project, or Build Alternative, would extend the existing Valley Metro light rail line south of Downtown along Central and 1st Avenues in central Phoenix. Noise concerns associated with a light rail system include light rail operations; effects from special trackwork, track curvature, audible warnings and traction power substations (TPSSs) and construction of the system. Vibration concerns associated with a light rail system include light rail operations, effects from special trackwork and construction of the system. More information about light rail noise and vibration concerns can be found in Section 1.0. Noise and vibration has been assessed in accordance with guidelines specified in the Federal Transit Administration (FTA) Noise and Vibration Impact Assessment guidance manual (FTA Report FTA-VA-90-1003-06, May 2006; also referred to as FTA Guidance Manual). Specifics of criteria applied can be found in Section 2.0, and specifics of the prediction methodologies can be found in Section 3.0. Potential impacts were examined for locations adjacent to the proposed alignment for both transit operations and construction activities. Noise- and vibration-sensitive land uses along the alignment include many single- and multifamily residences, hotels, schools, courthouses, libraries, religious and cultural institutions, a habitat restoration area and medical facilities. A full list of sensitive receivers and maps showing their locations can be found in Appendix F. A noise and vibration measurement program was conducted to characterize the existing noise and vibration in the project area. The primary existing noise sources in the area are vehicular traffic along the whole alignment and airplane noise north of Elwood Street. Normalized to a distance of 25 feet from the near travel lane, 24-hour noise levels (Ldn) ranged from 69 to 74 dBA; note that the Ldn metric applies penalties for nighttime noise to properly assess residential land uses. Also at a distance of 25 feet, short-term (up to 1 hour) noise levels ranged from 68 to 74 dBA Leq, representing the worst noise hour (highest traffic volumes during free-flowing traffic conditions). More information about the 2015 conditions can be found in Section 4.0. The vibration test program included propagation tests to characterize efficiency of vibration propagation through the ground at several locations along the alignment. Vibration propagation was found to be very efficient along the whole alignment, with peak efficiency in the 40 to 50 Hz range. The existing vibration data helped to confirm the validity of the propagation data. More information about vibration propagation can be found in Section 4.0.

SUMMARY OF NOISE IMPACT ANALYSIS

This section summarizes the results of the noise impact assessment for the South Central Light Rail Extension Project (more details can be found in Section 5.0). The predicted noise levels for light rail operations include the noise from the steel wheels of the light rail rolling on the steel rails and the noise from special trackwork, train bells as Noise and Vibration Technical Report ES-1 March 2016 Environmental Assessment South Central Light Rail Extension

the light rail vehicle (LRV) arrives and departs from stations or passes through an intersection, crossing gate bells at the roundabouts and TPSS units. The impact analysis does not include noise from warning horns because they would only be used in case of emergency. Noise levels from TPSS units were also assessed separately for nighttime noise at nearby residential properties. The TPSS units are the only ancillary noise source associated with the project. The noise-sensitive receivers where potential impact is predicted are presented in Table ES-1, along with noise limit exceedances and mitigation recommendations. Impact exceedance is shown as exceedance of a moderate impact level (with severe impact noted). For the South Central Light Rail Extension Project, mitigation is recommended for two residential sensitive receiver clusters (FTA Category 2) as described below. For exceedances less than 1 dB, mitigation is not recommended.

• A potential moderate impact with an exceedance of 3 dB is predicted for receiver cluster SB-42, two residences on the southbound side just north of the Western Canal. This impact is caused by the nearby special trackwork just north of the Central Avenue/Baseline Road station. Installing a low-impact frog for the special trackwork would eliminate the impact. Low-impact frogs can reduce noise levels by creating a smoother transition through the gap in the rails at the special trackwork. Examples of low-impact frogs include moveable point frogs, spring-rail frogs, monoblock frogs or flange-bearing frogs (refer to Appendix G for more information).

• A potential severe impact with predicted levels meeting the severe limit (and exceeding the moderate limit by 5 dB) occurs at receiver cluster NB-13, two residences on the northbound side near the intersection of Central Avenue/Raymond Street. This impact is caused by nearby special trackwork and a nearby TPSS unit. Mitigation for both the special trackwork and the TPSS unit is necessary to eliminate the impact. A low-impact frog is recommended for the special trackwork. To mitigate the noise from the TPSS unit, it should be strategically located within the site, with the major noise source, the cooling fans, being as far from the residences as possible. If the TPSS unit is located within the parcel as far as feasible and oriented with the cooling fans facing away from the sensitive receivers, the predicted noise level could be reduced to below the applicable threshold. The cooling fans on the TPSS unit should be facing east or south and be located more than 50 feet from the nearest residence to reduce the predicted noise levels to below the impact threshold (when combined with the low-impact frog). If there is not much flexibility on where to locate the unit within the parcel, a sound enclosure should be built around the TPSS unit to reduce noise levels at sensitive receivers; the sound enclosure would need to reduce noise by 3.4 dB, which is attainable with a proper design of the enclosure (appropriately considers the cooling fan height above ground). Since only five of the six TPSS locations being evaluated will be chosen, it may be possible to eliminate this location as an option and thus remove the TPSS unit as a sound source for nearby receivers.

Note that for all predictions and mitigation recommendations, it is assumed that the track and wheels would be maintained in a state of good repair (that is, rail corrugations and wheel flats would be minimized through maintenance procedures—rail grinding and wheel truing).

Noise and Vibration Technical Report ES-2 March 2016 Environmental Assessment South Central Light Rail Extension

Also note that potential wheel squeal would be addressed for the infrequent, nonrevenue train movements at the following locations with track curvature: 1st Avenue/McKinley Street, Central Avenue/McKinley Street, Central Avenue/Jefferson Street, 1st Avenue/Sherman Street and Central Avenue/Sherman Street. Wheel squeal is minimized with friction control. Two approaches to friction control are (1) applying a friction modifier to the rail head and/or the wheel tread or (2) applying lubricant to the gauge face of the rail or the wheel flange. Valley Metro vehicles are equipped with a lubrication system and are used on all track curvatures. All new light rail vehicles will also be equipped with a lubrication system. There are no revenue service train movements through low-radius curves.

TABLE ES-1: SUMMARY OF PREDICTED NOISE IMPACTS AND MITIGATION FOR LIGHT RAIL OPERATIONS

FTA Category of Land

Uses IDa Desc.b

Sensitive Receiver Location

Amount Exceeds

FTA Impact Threshold

(dB)c

# Impacted Units

without Mitigation

Recommended Mitigationd

Category 1 — — — — — —

Category 2

NB-13 SF 7–13 E Raymond Street

5e 2

Use low-impact frog for special trackwork at Raymond St; strategic placement/orientation of TPSS unit

SB-42 SF

7252 S Central Ave, 1st row, and 7246 S Central Ave

3 2 Use low-impact frog for special trackwork in the vicinity of Western Canal

Category 3 — — — — — — a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SF = single-family c Moderate limit exceedance. d Mitigation not recommended for exceedances less than 1 dB. e This exceedance qualifies as a severe impact. The South Central Light Rail Extension Project would involve some physical roadway changes and bus headway changes. Also, traffic volume differences are predicted for the Build and No-Build Alternatives. Evaluating changes with the Federal Highway Administration (FHWA) Traffic Noise Model (TNM), it is concluded that traffic changes would result in minimal or negligible sound level differences. As a result, these changes are not included in the project noise predictions. The park-and-ride lots to be used for the project consist of one at Broadway Road/Central Avenue, one near Fremont Road/Central Avenue (near the proposed Baseline Road/Central Avenue station) and two existing lots along Baseline Road, one east of Central Avenue and the other west of Central Avenue. Applying FTA


procedures, it is predicted that the park-and-ride lot noise at Broadway Road/Central Avenue is far below the existing noise, resulting in no increase in noise at the surrounding receivers. For the park-and-ride lot near Fremont Road/Central Avenue, it was determined that all lot noise levels were below existing noise levels. When the lot noise level was close to the existing noise level, further analysis was done that showed the lot noise does not contribute to potential project noise impacts for the nearby receivers. For the existing lots on Baseline Road, no substantial change to current use is anticipated as a result of the project. Therefore, these lots require no further consideration of noise impact. Although the proposed project includes planned improvements to the facilities at the existing site for the Operations and Maintenance Center, east of Phoenix Sky Harbor International Airport and southwest of the intersection of the Grand Canal and Loop 202, no receivers in the vicinity are sensitive to noise and vibration impacts. As a result, no noise or vibration impacts are predicted. In summary, with implementation of mitigation where needed, the proposed project would not result in exceedances of the applicable noise criteria thresholds. Therefore, the project would have no significant adverse noise impact.

SUMMARY OF VIBRATION IMPACT ANALYSIS

This section summarizes the results of the vibration impact assessment for the South Central Light Rail Project (more details can be found in Section 5.0). The vibration-sensitive receivers where impact is predicted are presented in Table ES-2. Below is a summary of the predicted impacts and recommended mitigation. Impacts are predicted at two multifamily residential receivers Downtown, including the Palomar Hotel and Barrister Place. Groundborne noise and vibration impacts are predicted because of the proximity of the track (approximately 20 feet) as well as the presence of special trackwork. The Barrister Place building is currently vacant, but is planned for a multiuse redevelopment that will include a residential component. If it is not possible to relocate either the track or the special trackwork farther away from the Palomar Hotel or Barrister Place, then the recommended mitigation for the Palomar Hotel and Barrister Place is installation of isolated slab track. The design consists of a concrete slab supported by a continuous elastomeric support mat. This design is capable of attenuation greater than 10 dB at frequencies of 25 Hz and higher. A less than 1 VdB exceedance of the vibration criteria threshold is anticipated for three single-family homes at cluster NB-07 on Central Avenue. A less than 1 dB exceedance of the groundborne noise criteria is also expected at the Arizona Summit Law School (NB-A) and the Maricopa County Courthouse (NB-B). At these locations, a rail boot, a resilient material between the rail and the receiver, is the recommended mitigation measure. The most common design for embedded track on modern light rail systems is to use a rubber boot around the rail with the rail and boot embedded in concrete. The standard-booted embedded track system is relatively stiff and does not provide much isolation. However, several suppliers have developed embedded track systems that incorporate much softer rubber elements. Where relatively limited vibration attenuation is required, one of these systems would provide sufficient vibration attenuation.


The proposed project is expected to exceed the vibration impact levels at the Salvation Army Adult Rehabilitation Center (NB-C) by less than 1 VdB and the groundborne noise threshold levels by approximately 10 dB. The recommended mitigation is to install a rail boot and a low-impact frog (described more in the next paragraph). For all other sensitive uses presented in Table ES-2, installation of low-impact frogs at the nearby special trackwork, such as loops and crossovers, is the recommended measure to mitigate groundborne noise and/or vibration impacts at these locations. The gaps in the rail associated with standard frogs can cause vibration levels to increase by up to 10 decibels. Low-impact frogs can reduce vibration levels by creating a smoother transition through the gap in the rails at the special trackwork. Examples of low-impact frogs include monoblock frogs, flange-bearing frogs, moveable point frogs or spring rail frogs. Where possible, special trackwork may also be relocated farther away from the receiver. More information on low-impact frogs is included in Appendix G. With implementation of the recommended mitigation where needed, the proposed project would not result in exceedances of the applicable groundborne noise or vibration criteria thresholds. Therefore, the project would have no significant adverse groundborne noise or vibration impacts.

TABLE ES-2: SUMMARY OF PREDICTED VIBRATION IMPACTS AND APPLICABLE MITIGATION AT RESIDENTIAL RECEIVERS

IDa Desc.b Sensitive Receiver Location

GBV (VdB)

GBN (dBA)

Recommended Mitigation

Mitigation, Feet

Beyond Edge of Building

Total Length of Mitigation

Lim

it

Pred

ict

Lim

it

Pred

ict

NB-01 HT Hotel Palomar Phoenix 72 78 44 53 Isolated slab

track 65

480 NB-02 MF

Barrister Place (potential multiuse redevelopment with residential component)

72 77 43 53 Isolated slab track 65

NB-07 SF 1001–1009 S Central Ave 72 72c 50 47 Rail boot 60 280

SB-11 SF 3716 S Central Ave 72 74 51 48 Low-impact frog — —

SB-23 SF

S Central Ave and W Cody Dr, 1st and 2nd rows

72 75 50 49 Low-impact frog — —

SB-42 SF



NB-A SC Arizona Summit Law School 78 66 40 40c Rail boot 55 210


TABLE ES-2: SUMMARY OF PREDICTED VIBRATION IMPACTS AND APPLICABLE MITIGATION AT RESIDENTIAL RECEIVERS


GBV (VdB)

GBN (dBA)

Recommended Mitigation

Mitigation, Feet



Lim

it

Pred

ict

Lim

it

Pred

ict

NB-B Court Maricopa County Justice Courts

78 67 41 41c Rail boot 40 230

NB-C MD Salvation Army Adult Rehab Center

78 78c 43 53 Low-impact frog, Rail boot

65 480

NB-G CH Revealed Word Church 78 78c 52 52c Low-impact frog — —

SB-N SC Phoenix Collegiate Academy


a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SF = single-family residential, MF = multifamily residential, Court = government courthouse, MD = medical center, CH = church, SC = school c Levels are reported to the nearest decibel. These numbers represent fractional exceedances of less than 1 dB (still considered an impact).

Note that historic structures that do not fall into the FTA land use categories are not included in the assessment for vibration impact from light rail operations. The vibration impact thresholds are based on annoyance, and the primary concern for historic structures is the risk of damage. The recommended limit in the FTA Guidance Manual for buildings extremely susceptible to damage is 90 VdB, which is 18 decibels higher than the limit for Category 2 (residential) land uses. Vibration from light rail operations will be well below the limit for buildings extremely susceptible to damage at all historic resources. In summary, with implementation of mitigation where needed, the proposed project would not result in exceedances of the applicable groundborne noise or vibration criteria thresholds. Therefore, the project would have no significant adverse groundborne noise or vibration impact.

SUMMARY OF CONSTRUCTION NOISE AND VIBRATION IMPACT ANALYSIS

Construction Noise

Construction noise levels were predicted using estimates of the types of equipment likely to be used during the noisiest periods of track construction. The predicted construction noise level exceeds the FTA impact threshold for construction noise by 4 decibels at 50 feet. Given that some residences in the project area are within 50 feet of the alignment, construction noise impacts are likely unless the contractor is required to implement noise control measures when working near residences.


Listed below are some typical approaches to reducing noise levels associated with the construction phase of major projects. Requiring the contractor to employ these methods should leave the contractor with enough flexibility to perform the work without undue financial or logistical burdens while protecting adjacent noise sensitive receivers from excessive construction noise levels.

• Avoid nighttime construction when possible. If nighttime construction is necessary, develop nighttime noise limits.

• Use specialty equipment with enclosed engines and/or high-performance mufflers.

• Locate equipment and staging areas as far from noise-sensitive receivers as possible.

• Limit unnecessary idling of equipment.

• Install temporary noise barriers. This approach can be particularly effective for stationary noise sources such as compressors and generators.

• Reroute construction-related truck traffic away from local residential streets.

• Avoid impact pile driving where possible. Where geological conditions permit, the use of drilled piles or a vibratory pile driver is generally quieter.

Specific measures to be employed to mitigate construction noise impacts should be developed by the contractor and presented in the form of a Noise Control Plan.

Construction Vibration

The primary concern regarding construction vibration is potential damage to structures. The thresholds for potential damage are much higher than the thresholds for evaluating potential annoyance used to assess impact from operational vibration. At a distance of 50 feet from buildings, the predicted vibration levels from construction are below the damage risk criteria for even those buildings most sensitive to damage. At a distance of 25 feet, the vibration level from high-vibration-generating equipment, such as a vibratory roller, is predicted to exceed the impact threshold for timber and masonry buildings and those buildings most susceptible to damage. It is unlikely that high-vibration-generating equipment, such as a vibratory roller, would be operated closer than 25 feet of the nearest buildings. However, the following precautionary vibration mitigation strategies should be implemented to minimize the potential for damage to any structures in the corridor: 1. Preconstruction Survey: The survey should include inspecting building foundations

and taking photographs of preexisting conditions. The survey can be limited to buildings within 25 feet of high-vibration-generating construction activities. The only exception is if an important and potentially fragile historic resource is located within approximately 200 feet of construction, in which case it should be included in the survey.

2. Vibration Limits: The FTA Guidance Manual suggests vibration limits in terms of peak particle velocity ranging from 0.12 inches/second for “buildings extremely susceptible to vibration damage” to 0.5 inches/second for “Reinforced-concrete,


steel or timber” buildings. The contract specifications should limit construction vibration to a maximum of 0.5 inches/second for all buildings in the corridor. Should the preconstruction survey identify any buildings that are particularly sensitive to vibration, these structures should be assessed by an architectural historian to determine appropriate vibration limits.

3. Vibration Monitoring: The contractor should be required to monitor vibration at any buildings where vibratory rollers or similar high-vibration-generating equipment would be operated within 25 feet of buildings and at any location where complaints about vibration are received from building occupants.

4. Alternative Construction Procedures: If high-vibration construction activities would be performed close to structures, it may be necessary for the contractor to use an alternative procedure that produces lower vibration levels. Examples of high-vibration construction activities include the use of vibratory compaction or hoe rams next to sensitive buildings. Alternative procedures include use of nonvibratory compaction in limited areas and a concrete saw in place of a hoe ram to break up pavement.

Three historic towers, the Luhrs Tower, Luhrs Building and Barrister Place building, are located along the alignment in Downtown Phoenix. The Luhrs Tower, located at the southeast corner of Jefferson Street and First Avenue, is about 26 feet from the closest track. The Luhrs Building, located at the southwest corner of Jefferson Street and Central Avenue, is about 36 feet from the nearest track. The Barrister Place building is located about 21 feet from the nearest track. Although these buildings are historic, they are not necessarily extremely sensitive to vibration. As discussed in Section 6.2, predicted vibration levels from construction equipment do not exceed the construction vibration limit for these buildings. No adverse effect from construction vibration is predicted for the Luhrs Tower, Luhrs Building or the Barrister Place building. Although no adverse effect is predicted, both should be included as part of the preconstruction survey to document 2015 conditions.


TABLE OF CONTENTS

EXECUTIVE SUMMARY ................................................................................................. 1

SUMMARY OF NOISE IMPACT ANALYSIS ........................................................... 1

SUMMARY OF VIBRATION IMPACT ANALYSIS ................................................... 4

SUMMARY OF CONSTRUCTION NOISE AND VIBRATION IMPACT ANALYSIS ...................................................................................................... 6 Construction Noise .......................................................................................... 6 Construction Vibration ..................................................................................... 7

1.0 INTRODUCTION ..................................................................................................... 1

1.1 BUILD ALTERNATIVE .................................................................................... 1 1.1.1 Stations ................................................................................................ 7 1.1.2 Traffic and Roadway Modifications ...................................................... 7 1.1.3 Transit Service Modifications ............................................................... 8 1.1.4 Parking ................................................................................................. 9 1.1.5 Operations and Maintenance Center Expansion .................................. 9

1.2 NOISE CONCERNS ASSOCIATED WITH THE LIGHT RAIL SYSTEM ....... 10

1.3 VIBRATION CONCERNS ASSOCIATED WITH THE LIGHT RAIL SYSTEM ....................................................................................................... 12

2.0 REGULATORY FRAMEWORK ............................................................................. 13

2.1 STATE AND LOCAL NOISE AND VIBRATION LIMITS ................................ 13

2.2 FTA NOISE IMPACT CRITERIA ................................................................... 13

2.3 FTA IMPACT CRITERIA FOR GROUNDBORNE VIBRATION ..................... 18

3.0 NOISE AND VIBRATION METHODOLOGY ......................................................... 23

3.1 NOISE ASSESSMENT APPROACH ............................................................ 23

3.2 NOISE PREDICTION MODEL ...................................................................... 23 3.2.1 Noise from Train Operations .............................................................. 23 3.2.2 Prediction Model, Noise from Audible Warnings ................................ 26 3.2.3 Ancillary Equipment............................................................................ 27 3.2.4 Road Traffic Analysis ......................................................................... 27 3.2.5 Park-and-Ride Analysis ...................................................................... 28

3.3 VIBRATION ASSESSMENT APPROACH .................................................... 28

3.4 VIBRATION PREDICTION MODEL .............................................................. 29 3.4.1 Vibration Propagation Test Procedure ............................................... 30 3.4.2 Vibration Propagation Test Sites ........................................................ 31 3.4.3 Applying Vibration Propagation Test Results to Prediction Model ...... 32 3.4.4 FDL .................................................................................................... 35 3.4.5 Adjustments of Lv for Prediction Model .............................................. 36 3.4.6 Final Vibration Prediction Model ......................................................... 37

Noise and Vibration Technical Report i March 2016 Environmental Assessment South Central Light Rail Extension

4.0 AFFECTED ENVIRONMENT ................................................................................ 39

4.1 2015 CONDITIONS – NOISE ....................................................................... 39

4.2 2015 CONDITIONS – VIBRATION ............................................................... 44

5.0 POTENTIAL OPERATIONAL NOISE AND VIBRATION IMPACTS AND MITIGATION ......................................................................................................... 48

5.1 LIGHT RAIL-RELATED NOISE ..................................................................... 48 5.1.1 Operational Noise .............................................................................. 48 5.1.2 Ancillary Equipment............................................................................ 57 5.1.3 Traffic Noise Attributable to Roadway and Traffic/Bus Volume

Changes ............................................................................................. 58 5.1.4 Other Noise ........................................................................................ 59

5.2 LIGHT RAIL OPERATIONAL VIBRATION .................................................... 60

5.3 OPERATIONAL NOISE MITIGATION .......................................................... 70

5.4 OPERATIONAL VIBRATION MITIGATION .................................................. 72

6.0 POTENTIAL CONSTRUCTION NOISE AND VIBRATION IMPACTS AND MITIGATION ......................................................................................................... 75

6.1 CONSTRUCTION NOISE ............................................................................. 75

6.2 CONSTRUCTION VIBRATION ..................................................................... 76

6.3 CONSTRUCTION NOISE MITIGATION ....................................................... 78

6.4 CONSTRUCTION VIBRATION MITIGATION ............................................... 78

7.0 REFERENCES ...................................................................................................... 80

APPENDIXES

APPENDIX A. FUNDAMENTALS OF NOISE AND VIBRATION .................................. A-1 APPENDIX B. FORCE DENSITY MEASUREMENT RESULTS .................................. B-1 APPENDIX C. NOISE SOURCE LEVEL ..................................................................... C-1 APPENDIX D. VIBRATION PROPAGATION TEST RESULTS .................................. D-1 APPENDIX E. AMBIENT NOISE AND VIBRATION MEASUREMENT SITES ............. E-1 APPENDIX F. SENSITIVE RECEIVER INVENTORY .................................................. F-1 APPENDIX G. VIBRATION MITIGATION FOR SWITCHES ....................................... G-1

Noise and Vibration Technical Report ii March 2016 Environmental Assessment South Central Light Rail Extension

TABLES

TABLE ES-1: SUMMARY OF PREDICTED NOISE IMPACTS AND MITIGATION FOR LIGHT RAIL OPERATIONS ......................................................................... 3

TABLE ES-2: SUMMARY OF PREDICTED VIBRATION IMPACTS AND APPLICABLE MITIGATION AT RESIDENTIAL RECEIVERS .............................. 5

TABLE 1: SOUTH CENTRAL LIGHT RAIL EXTENSION AT-A-GLANCE ....................... 3 TABLE 2: PLANNED STATION LOCATION, BY TYPE .................................................. 7 TABLE 3: FTA LAND USE CATEGORIES AND NOISE METRICS .............................. 14 TABLE 4: FTA NOISE IMPACT CRITERIA ................................................................... 15 TABLE 5: FTA GROUNDBORNE VIBRATION AND GROUNDBORNE NOISE

IMPACT CRITERIA ............................................................................................ 19 TABLE 6: INTERPRETATION OF VIBRATION CRITERIA FOR DETAILED

ANALYSIS .......................................................................................................... 21 TABLE 7: GROUNDBORNE NOISE AND VIBRATION IMPACT CRITERIA FOR

SPECIAL BUILDINGS ........................................................................................ 21 TABLE 8: PROPOSED TRAIN OPERATING SCHEDULE ........................................... 25 TABLE 9: LSTM COEFFICIENTS FOR PREDICTION MODEL .................................... 35 TABLE 10: SUMMARY OF EXISTING NOISE MEASUREMENTS ............................... 43 TABLE 11: SUMMARY OF EXISTING VIBRATION MEASUREMENTS ....................... 46 TABLE 12: SUMMARY OF NOISE IMPACT ASSESSMENT FOR CATEGORY 2 ....... 50 TABLE 13: SUMMARY OF NOISE IMPACT ASSESSMENT FOR CATEGORY 3 ....... 55 TABLE 14: PREDICTED NIGHTTIME TPSS NOISE .................................................... 58 TABLE 15: SUMMARY OF VIBRATION IMPACT ASSESSMENT FOR

CATEGORY 2 .................................................................................................... 63 TABLE 16: SUMMARY OF VIBRATION IMPACT ASSESSMENT FOR

CATEGORY 3 .................................................................................................... 68 TABLE 17: SUMMARY OF RECOMMENDED NOISE MITIGATION ............................ 71 TABLE 18: SUMMARY OF VIBRATION MITIGATION FOR SENSITIVE

RECEIVERS ....................................................................................................... 74 TABLE 19: CONSTRUCTION NOISE GUIDELINES .................................................... 75 TABLE 20: PREDICTED CONSTRUCTION NOISE AT 50 FEET ................................. 76 TABLE 21: CONSTRUCTION VIBRATION DAMAGE RISK CRITERIA ....................... 77 TABLE 22: CONSTRUCTION VIBRATION PREDICTIONS ......................................... 77

Noise and Vibration Technical Report iii March 2016 Environmental Assessment South Central Light Rail Extension

FIGURES

FIGURE 1: BUILD ALTERNATIVE .................................................................................. 2 FIGURE 2: OPERATIONS AND MAINTENANCE CENTER EXPANSION ................... 10 FIGURE 3: FTA NOISE IMPACT CRITERIA ................................................................. 17 FIGURE 4: FTA CRITERIA FOR DETAILED VIBRATION ANALYSIS.......................... 20 FIGURE 5: SCHEMATIC OF VIBRATION PROPAGATION TEST ............................... 30 FIGURE 6: BEST-FIT LSTM AT ALL SITES ................................................................. 33 FIGURE 7: BEST-FIT LSTM – MAXIMUM, MINIMUM AND AVERAGE OF ALL

SITES ................................................................................................................. 34 FIGURE 8: LIGHT RAIL FORCE DENSITY LEVEL AT 30 MPH ................................... 36 FIGURE 9: PREDICTED LRV VIBRATION SPECTRUM AT 30 MPH .......................... 38

Noise and Vibration Technical Report iv March 2016 Environmental Assessment South Central Light Rail Extension

1.0 INTRODUCTION

This Noise and Vibration Technical Report was prepared to support the Environmental Assessment (EA) for the proposed South Central Light Rail Extension Project in Phoenix, Arizona. The proposed project, or Build Alternative, consists of a southern extension of the existing Valley Metro light rail line along Central and 1st Avenues in central Phoenix. The extension would begin in Downtown Phoenix where it would connect with the existing light rail line at Central Avenue and Washington Street (northbound) and 1st Avenue and Jefferson Street (southbound) and extend to its southern terminus at Central Avenue and Baseline Road, a distance of 5 miles. In addition to the main text that addresses the regulatory framework, noise and vibration prediction methodologies, the affected environment, potential noise and vibration impacts and mitigation for operations and construction, the document includes the following appendices:

• Appendix A: Fundamentals of Noise and Vibration

• Appendix B: Force Density Measurement Results

• Appendix C: Noise Source Level

• Appendix D: Vibration Propagation Test Results

• Appendix E: Ambient Noise and Vibration Measurement Sites

• Appendix F: Sensitive Receiver Inventory

• Appendix G: Vibration Mitigation for Switches

The remainder of this section discusses the Build Alternative for the project, including specific project features. In addition, a brief review of potential noise and vibration concerns related to the project is provided.

1.1 BUILD ALTERNATIVE

The extension tracks would connect to the existing light rail system at Central Avenue and Washington Street in the northbound direction and at 1st Avenue and Jefferson Street in the southbound direction. The track would continue south along 1st and Central Avenues to Hadley Street, where the southbound track would follow the 1st Avenue one-way couplet curve to the east to rejoin Central Avenue. From Hadley Street to the extension’s southern terminus at Baseline Road, the tracks would operate bidirectionally along Central Avenue. The South Central Light Rail Extension Project is scheduled to begin operations in 2023. Primary features of the light rail extension are summarized in Table 1. The alignment would be primarily at grade, with the exception of where Central and 1st Avenues go under the Union Pacific Railroad and Jackson Street overpasses between Buchanan and Madison Streets. The track guideway would be exclusively reserved for light rail vehicles, physically separated from automobile traffic by a barrier such as a trackway curb. Additional information regarding specific project features follows the summary table. Noise and Vibration Technical Report 1 March 2016 Environmental Assessment South Central Light Rail Extension

FIGURE 1: BUILD ALTERNATIVE

Noise and Vibration Technical Report 2 March 2016 Environmental Assessment South Central Light Rail Extension

TABLE 1: SOUTH CENTRAL LIGHT RAIL EXTENSION AT-A-GLANCE

Feature Description From – To: Central Ave and 1st Ave (one-way couplet); Washington St/Jefferson St (from

connection with existing light rail) to Hadley St – This section has a single-track configuration. Central Ave – Hadley St to Baseline Rd – This section has a double-track configuration.

Route distance Approximately 5 miles

Daily ridership 6,690a

Operations begin

2023

Construction timing and duration

• Timing: 2019 to 2023 • Duration: Approximately 4 years

Trackwork • Southbound: Side-running track along 1st Ave south of Jefferson St to Lincoln St; transitions to median-running along 1st Ave to Hadley St; follows the 1st Ave one-way couplet curve to the east to rejoin Central Ave and continues median-running to Baseline Rd

• Northbound: Median-running track from Baseline Rd to Buchanan St; side-running track between Buchanan St and Madison St; transitions to median-running from Madison St to Jefferson St; transitions back to side-running to connect into existing station north of Jefferson St

• Typically at grade except where both the northbound and southbound tracks and roadway go under Union Pacific Railroad and Jackson St (between Buchanan St and Madison St)

• Continuously welded steel rails • Track rails embedded in a concrete slab for aesthetic purposes and to provide level

and smooth crossings for automobiles and pedestrians where such crossings are allowed

Special trackwork • Loop at McKinley St/1st Ave and McKinley St/Central Ave (northern portion of the

study area) – provides operational flexibility during special events and in case of track closures by allowing the train to switch tracks

• Loop near Sherman St (south of Grant St) to allow trains to change tracks and/or direction

• Crossover tracks at Central Ave/Jefferson St to allow light rail vehicle nonrevenue service to operate to the Operations and Maintenance Center near 48th St and Washington St

• Crossover tracks to facilitate movement of trains to opposite track at following locations: Sherman St, Cocopah St, Raymond St, Cody Dr, Sunland Ave and Fremont Road/Jesse Owens Pkwy

• Central Ave/Baseline Rd station would have four tracks: two for loading and unloading passengers on the station platform in both directions and two outside tracks for temporary train storage


Stations Eight new stations would be provided at:

• Lincoln St/1st Ave (southbound) • Lincoln St/Central Ave (northbound) • Buckeye Rd/Central Ave • Audubon Center/Central Ave • Broadway Rd/Central Ave • Roeser St/Central Ave • Southern Ave/Central Ave • Baseline Rd/Central Ave (southern terminus) The light rail extension would tie into the existing light rail tracks just south of the existing stations at Washington St/Central Ave (northbound operations) and Jefferson/1st Ave (southbound operations). Here, the South Central trains would interline with the existing light rail line and continue north to serve all existing stations between Washington St/Jefferson St and the line’s terminus at Dunlap Ave/19th Ave.

Light rail vehicles

• 18 total – 15 revenue service vehicles to accommodate peak operations and 3 spare vehicles

• Vehicle specifications similar to Valley Metro’s existing fleet for system operability • Carry approximately 175 passengers per vehicle • Average operating speed of approximately 20 miles per hour, with a maximum

speed of 35 miles per hour • Could operate as a two- or three-car train depending on demand (two-car train

would be the most common configuration) Traffic lanes Light rail would operate in semiexclusive guideway separate from vehicular traffic,

except at signal-protected intersections, which would require changes in the configuration of traffic lanes as follows: Southbound • 1st Ave from Jefferson St to Lincoln St, including the pass under the Jackson St

Bridge and Union Pacific Railroad (UPRR) bridge, traffic lanes reduced from three through lanes to two through lanes with turn pockets at minor signalized intersections

• 1st Ave from Lincoln St to Hadley St, traffic lanes reduced from two through lanes to one through lane with left-turn pocket at minor signalized intersection

• Central Ave from Hadley St to Apache St, traffic lanes reduced from two in each direction to one in each direction with left-turn pockets at minor signalized intersections

• Central Ave from approximately Apache St to Watkins St, including the pass under the Interstate 17 (I-17) bridge, two through traffic lanes maintained each direction with left-turn pocket at I-17 frontage roads

• Central Ave from Watkins St to Baseline Rd, including the Salt River bridge and Western Canal bridge, traffic lanes reduced from two in each direction to one in each direction with left-turn pockets at minor signalized intersections

• At Buckeye Rd/Central Ave, Broadway Rd/Central Ave, Southern Ave/Central Ave and Baseline Rd/Central Ave, intersections flare to include one through lane, one dedicated left-turn lane and one shared lane for bicycles and right turns


Traffic lanes (continued)

Northbound • Central Ave from Baseline Rd to Watkins St, including the Salt River bridge and

Western Canal bridge, traffic lanes reduced from two in each direction to one in each direction with left-turn pockets at minor signalized intersections

• Central Ave from approximately Watkins St to Apache St, including the pass under the I-17 bridge, two through traffic lanes maintained each direction with left-turn pocket at I-17 frontage roads

• Central Ave from Apache St to Lincoln St, traffic lanes reduced from two through lanes to one in each direction with left-turn pockets at minor signalized intersections

• Central Ave from Lincoln St to Madison St, including the pass under the UPRR bridge and the Jackson St bridge, traffic lanes reduced from three through lanes to two through lanes

• Central Ave from Madison St to Jefferson St, traffic lanes reduced from three through lanes to two dedicated right-turn lanes

• Central Ave from Jefferson St to Washington St, including the pass under the CityScape pedestrian bridge, roadway closed to through traffic

• Flared intersections as described for the southbound direction Roundabouts • Central Ave at Victory St • Central Ave just south of the Salt River in front of the Audubon Center I-17 Frontage Roads • Relocation of frontage roads away from the I-17 bridge

Sidewalks/ Bicycle routes

• Sidewalks to be maintained as currently exist • The Build Alternative would maintain bicycle routes as they currently exist, with

some reconfiguration. In some locations the bicycle lane would share right-of-way (ROW) with the dedicated right-turn lane and, in others, bicycle lanes may shift to the opposite side of the street.

• New bicycle lanes would be added at some locations where there currently are none to provide continuous bicycle lanes in both directions on 1st Ave/Central Ave between Madison St and Baseline Rd. To accomplish this would require new bicycle lanes at the following locations: o Southbound on 1st Ave between Madison St and Lincoln St o Southbound on Central Ave between Riverside St and Broadway Rd o Southbound and northbound (both directions) on Central Ave between

Southern Ave and Baseline Rd

Headways 12-minute frequency in each direction for most of the day, and 20 minutes during late night and early morning hours. Headways by time period are presented below: • 5 a.m.–6 a.m. 20 minutes • 6 a.m.–7 p.m. 12 minutes • 7 p.m.–12 a.m. 20 minutes • 12 a.m.–3 a.m. 20 minutes (Friday and Saturday only)

Hours of operation

Sunday through Thursday: 19 hours (5 a.m. to 12 a.m.) Friday and Saturday: 22 hours (5 a.m. to 3 a.m.)


Overhead catenary system

Distributes electricity to light rail vehicles, traction power substations (TPSSs) and signaling and communication systems: • Steel poles support power line: o Pole height: about 25 feet o Pole spacing: typically 90 to 170 feet

• Poles normally located between the two bidirectional tracks; sometimes located on the side of the light rail trackway with the overhead electrical line suspended over the light rail tracks

TPSSs • Supply electricity for light rail operations • Approximate site right-of-way requirements: o Structure: 25 by 47 feet o Total site (access, utilities, setbacks, etc.): 65 by 90 feet

• Six TPSS sites being considered; only five would be selected: o Northwestern corner Central Ave/Hadley St o Northwestern corner Central Ave/Cocopah St o Southeastern corner Central Ave/Raymond St o Northeastern corner Central Ave/Sunland Ave o Northeastern corner Central Ave/Carter Rd o Southeastern corner Central Ave/Jesse Owens Pkwy

Signal buildings

• Generally combined with TPSSs, with the exception of a signal building only near Central Ave and Jefferson St at CityScapeb

• Signal building without TPSS approximate site requirements: o Structure: 16 by 39 feet o Total site: 56 by 80 feet

• Signal building combined with TPSS: o Structure: 25 by 65 feet o Total site: 65 by 105 feet

Operations and maintenance

Existing Valley Metro Operations and Maintenance Center, southeast of 41st St/Washington St, would be expanded to include: • Seven new storage tracks to increase vehicle storage capacity • A second cleaning platform • Expansion of the Maintenance of Equipment building including modifications or

extension of the existing mezzanine, office space, inspection pits and cranes All improvements accommodated within the footprint of the existing Operations and Maintenance Center; no additional property would be acquired

Park-and-ride • Broadway Rd/Central Ave: A 70- to 80-space park-and-ride lot to be built on City of Phoenix-owned property adjacent to the Ed Pastor Transit Center

• Baseline Rd/Central Ave: An optional approximately 365 space park-and-ride lot would be constructed on the western side of Central Ave just south of Fremont Rd. Additionally, passengers could use the existing park-and-ride lots west and east of this location at 27th Ave/Baseline Rd and 24th St/Baseline Rd, respectively; local Routes 77 and 77B would provide frequent service (15 minutes all day) between the park-and-rides and the light rail terminus at Baseline Rd/Central Ave

a FTA Stops projection daily linked trips on Build Alternative for 2013 b This signal house is in a dense urban environment that is continually changing. During final design, the location of the signal house would be determined. As is typical in this type of environment, the signal house would likely be located in an existing parking structure, basement or utility vault.


1.1.1 Stations

The South Central Light Rail Extension Project would serve eight planned stations along the route, as shown in Table 2. The platforms would be about 280 feet long by 16 feet wide to accommodate up to three-car trains; however, trains would typically have two cars. Like existing Valley Metro light rail stations, those on the South Central Light Rail Extension are expected to include such amenities as seating, low-water landscaping, unobtrusive shade, trash receptacles, static and dynamic signs and ticket vending and validation machines. Access to and from adjacent streets would be provided by the appropriate passenger circulation elements such as platforms, sidewalks, ramps and stairs. The South Central Light Rail Extension would be interlined with the existing light rail line so that those passengers destined as far north as the light rail line terminus at Dunlap Avenue/19th Avenue could do so without transferring to another train.

TABLE 2: PLANNED STATION LOCATION, BY TYPE

Location Platform Type Direction(s) Serving

Lincoln St/1st Ave Side platform on east curb Southbound Lincoln St/Central Ave Side platform on west curb Northbound Buckeye Rd/Central Ave Center platform Both directions Audubon Center/Central Ave Center platform Both directions Broadway Rd/Central Ave Center platform Both directions Roeser St/Central Ave Center platform Both directions Southern Ave/Central Ave Center platform Both directions Baseline Rd/Central Ave Center platform Both directions

1.1.2 Traffic and Roadway Modifications

Accommodating both automobile traffic and light rail operations while minimizing additional right-of-way needs would require changes to the traffic configuration along portions of the existing roadways. In addition, the traffic signals along Central Avenue would be optimized, as part of the City of Phoenix ongoing signal maintenance program, to maximize traffic movements and minimize stops and delays along the corridor. In the southbound direction, traffic lanes on 1st Avenue from Jefferson to Lincoln Streets would be reduced from three through lanes to two through lanes with turn pockets at minor intersections. On the portion of 1st Avenue from Lincoln to Hadley Streets, the number of through lanes would be reduced from two lanes to one lane with a left-turn pocket at Hadley Street. Upon rejoining Central Avenue at Hadley Street, southbound traffic lanes would be reduced from two lanes to one lane for the remainder of the corridor. In the northbound direction, traffic lanes on Central Avenue from Baseline Road to Hadley Street would be reduced from two through lanes to one through lane with left-turn pockets at minor intersections. On the portion of Central Avenue from Hadley to Lincoln Streets, the number of through lanes would be reduced from three lanes to one lane. On Central Avenue north of Lincoln Street, the number of through lanes would be reduced from three to two lanes. Flared intersections (to include one through lane, one dedicated left-turn lane and one shared lane for bicycles and right


turns in each direction) would be provided at four locations along Central Avenue: Buckeye Road, Broadway Road, Southern Avenue and Baseline Road. The Central Avenue Bridge over the Salt River would be reduced from 4 travel lanes to 2 travel lanes. A flared intersection at Central Avenue and Interstate 17 (I-17) would also be provided and would include two through lanes and one dedicated left-turn lane in each direction. The I-17 frontage roads would be shifted to the north and to the south away fromI-17 where they intersect with Central Avenue. This would allow adequate clearance of vehicles crossing perpendicular to the light rail overhead catenary system (OCS). The current vertical clearance of the I-17 bridge over Central Avenue is 13 feet-11 inches; this dimension is less than Valley Metro’s desired minimum design standard of 16 feet 0 inches. LRT vehicles can operate within the current vertical clearance, but to reduce the risk of frontage road traffic striking the high-voltage light rail OCS, both frontage roads would be moved outward from their current alignment up to 85 feet to provide clearance for higher-profile vehicles (for example, large trucks) crossing under the OCS. Modern roundabouts would be built at two street locations along Central Avenue (Victory Street and south of the Salt River just north of the existing access to the Audubon Center). The track through both roundabouts would be median running, allowing the movement of light rail vehicles through the center of the roundabouts. Through traffic and right-turn movements would be allowed when the train is approaching and passing through the roundabouts. Left-turn and U-turn movements would be restricted by train-activated crossing gates as the train approaches. Modern roundabouts have the advantage of reducing train travel times by allowing trains to maintain more consistent speeds as compared with stopping at signalized intersections. The roundabouts may also increase intersection capacity and improve traffic progression through intersections. In addition, turning movements would be simpler to maneuver, especially to and from the intersecting streets because access to these streets from either direction would be permitted. In addition to road changes along Central Avenue, there are a few proposed traffic mitigation measures on other roads (as part of this project) that warrant consideration for noise. These are: added right turn and through lanes at the 7th Street/I-17 Interchange, added right turn lanes at the 7th Avenue/I-17 Interchange, and added right turn lanes at the 7th Avenue/Southern Avenue intersection.

1.1.3 Transit Service Modifications

In addition to the traffic and roadway changes, the Build Alternative would entail the following changes to transit service:

• Elimination of the Central South Mountain East and West RAPID routes because of duplicative service with the new light rail extension.

• Addition of Route 77B to supplement the existing Route 77 service. Both Routes 77 and 77B would operate to and from the South Central Extension end-of-line station at Baseline Road/Central Avenue to existing park-and-ride facilities at 27th Avenue and Baseline Road and 24th Street and Western Canal. Like Route 77, Route 77B would have 30-minute peak/off-peak headways, which would improve total


headways between the park-and-rides and the light rail end-of-line station to 15-minute peak/off-peak headways.

1.1.4 Parking

A park-and-ride lot would be built to accommodate 70 to 80 vehicles near Central Avenue and Broadway Road. The lot would be built on property owned by the City of Phoenix located west of and adjacent to the Ed Pastor Transit Center. Parking for the end-of-line station at Baseline Road/Central Avenue would be provided in two ways: 1) a proposed park-and-ride lot and e 2) enhanced bus service between the Baseline Road/Central Avenue end-of-line light rail stations and two existing park and ride facilities along Baseline Road. The proposed park-and-ride lot near the Baseline Road/Central Avenue station would accommodate approximately 365 parking spaces and would be on the western side of Central Avenue between the northern end of the station and Fremont Road. Existing park-and-ride lots are located both west and east of the end-of-line station at 27th Avenue/Baseline Road and 24th Street/Baseline Road, respectively. Local Route 77 already serves both lots and includes a stop at Baseline Road/Central Avenue. Route 77B would be added as an overlay service for these same areas. Combined, these two routes would provide frequent service (15-minute frequencies all day) between the existing park-and-rides and the light rail terminus at Baseline Road/Central Avenue.

1.1.5 Operations and Maintenance Center Expansion

In conjunction with the Build Alternative, Valley Metro plans to expand the existing OMC, east of Phoenix Sky Harbor International Airport and southwest of the intersection of the Grand Canal and Loop 202 (Figure 2-18). The OMC expansion would include modifications to the MOE building, storage tracks and cleaning platform. The MOE building modifications would consist of an approximately 23,000-square-foot expansion to the east with improvements/modifications to the existing mezzanine, office space, inspection pits and cranes. Expansion of vehicle storage would include construction of seven new storage tracks (north and south of the existing storage tracks) to increase total storage capacity at the OMC. The storage tracks at the OMC were designed to accommodate 35 vehicles; however, the current Valley Metro fleet is 50 necessitating vehicles be stored in locations others than the storage tracks (i.e., inside the MOE building, the wash facility, and along the yard lead). The expansion of the OMC would accommodate approximately 100 vehicles on the storage tracks themselves allowing for more efficient operations at the OMC. Finally, two new tracks and a second cleaning platform would be constructed south of the existing cleaning platform. The OMC expansion would occur within the existing facility boundaries; thus, no additional property would be required.


FIGURE 2: OPERATIONS AND MAINTENANCE CENTER EXPANSION

1.2 NOISE CONCERNS ASSOCIATED WITH THE LIGHT RAIL SYSTEM

The following list summarizes most of the major noise sources associated with operating light rail systems: Light Rail Operations: This is the normal noise from the operation of light rail vehicles (LRVs) and includes noise from steel wheels rolling on steel rails (wheel/rail noise) and from propulsion motors, air conditioning and other auxiliary equipment on the vehicles. At the time of this study the maximum operating speed considered for the light rail ranges from 25 to 35 miles per hour (mph), depending on the section of the alignment. A key assumption in the noise predictions is that the optimal wheel and rail profiles would be maintained for the South Central Light Rail Extension through periodic truing of the wheels and rail grinding. Traffic Noise: Light rail shares the right-of-way with vehicular traffic, and the proposed project would result in a few physical changes to the road and also bus volume changes


in the project area. Only minimal changes in sound levels should be expected from these potential changes. Brief traffic analyses were conducted for the alignment to determine the following potentially influencing changes attributable to the project: road flaring at several intersections on Central Avenue, the new traffic roundabouts and bus volume changes (route-dependent increases and decreases). Audible Warnings: The LRVs would be equipped with horns and bells as audible warning devices. The horns would be used in the same manner as on the buses along the alignment to alert pedestrians and motor vehicles of a potential safety risk. The horns are not expected to be used frequently enough to have any effect on the noise exposure. Therefore, horn noise has not been included in the noise analysis. Because the train bells would be used on a regular basis at stations and traffic signals, bell noise was included in the analysis for all noise-sensitive receivers near the alignment. Since two roundabouts would be introduced as part of the project, bells from crossing gates were also included in the analysis. Parameters that affect these stationary bells include the level at which the bells would sound, the time the bells are sounding and whether or not a shroud is in place to provide directional sounding/shielding (analysis assumed no shrouds). It should be noted that Federal Transit Administration (FTA) criteria are not based on these types of sound sources that have abrupt onsets and are intentionally noticeable sounds with frequency content different from typical urban/suburban sound environments. Special Trackwork: The South Central Light Rail corridor would be constructed of continuously welded track, which eliminates the clickety-clack noise associated with older rail systems. The one exception is the special trackwork for loops and crossovers, where two rails must cross. A fixture called a frog is used where rails must cross. The wheel impacts at the gaps in the rails of a standard frog cause noise levels near special trackwork to increase by approximately 10 decibels (dB) at a distance of 35 feet. Low-impact frogs are available that smooth the transition through the gap in the rail and can be used as a mitigation measure where the noise from special trackwork results in a predicted impact. Examples of low-impact frogs include flange-bearing frogs, monoblock frogs, spring-rail frogs and moveable point frogs. More information on frogs can be found in Appendix G. Wheel Squeal: Wheel squeal is generated when steel-wheel transit vehicles traverse tight radius curves. It is very difficult to predict when and where wheel squeal will occur. A general guideline is that there is the potential for wheel squeal at any curve with a radius that is less than approximately 600 feet. There is the potential for the LRVs to generate wheel squeal on the sharper curves used for nonrevenue train movement. Common approaches to controlling wheel squeal include (1) applying a friction modifier to the railhead and/or the wheel tread, (2) applying lubricant to the gauge face of the rail or the wheel flange and (3) optimizing the wheel and rail profiles. Using resilient wheels and maintaining the tracks would help control wheel squeal; also, periodically truing wheels would maintain an optimum profile and can help minimize wheel squeal. Ancillary Equipment: The only ancillary equipment associated with the proposed project with potential for creating noise impacts are the traction power substation (TPSS) units. Although five TPSS locations are required for the light rail system, six potential locations have been identified. A general guideline is that locating the TPSS at least 50 feet from the closest residential land use would avoid noise impacts. Noise and Vibration Technical Report 11 March 2016 Environmental Assessment South Central Light Rail Extension

Construction: All the sources discussed above are associated with the operation of the proposed project. The use of heavy equipment during project construction has the potential to result in substantial but temporary increases in local noise levels along the corridor. Potential construction noise impacts are assessed separately from operational noise impacts.

1.3 VIBRATION CONCERNS ASSOCIATED WITH THE LIGHT RAIL SYSTEM

The following list summarizes most of the significant vibration sources associated with operating light rail systems: Light Rail Operations: Light rail operations create groundborne vibration that can be intrusive to occupants of buildings close to the tracks. This is particularly important for residential land uses that are located within 75 feet of LRVs operating at 30 mph. Note that the FTA impact criteria for vibration is based on annoyance and the predicted levels of light rail vibration at all receivers are well below the thresholds used to protect sensitive and fragile historic structures from damage. The potential for vibration from light rail operations to be annoying to occupants of historic structures is based on the appropriate vibration impact criteria for the current use of the building. A key assumption in the vibration predictions is that the optimal wheel and rail profiles would be maintained through periodic truing of the wheels and rail grinding. Special Trackwork: Loops and crossovers, where two rails cross, are the primary type of special trackwork on the alignment. This type of special trackwork is sometimes referred to as a frog. Standard frogs have gaps, and the train wheels must “jump” across the gap. The wheels striking the ends of the gap increase vibration levels as well as noise levels. The groundborne vibration levels near special trackwork increase by approximately 10 VdB because of wheel impacts at the gaps in the rails. Similar to noise, low-impact frogs can be used as a mitigation measure where the vibration from special trackwork results in a predicted vibration impact. More information on low-impact frogs can be found in Appendix G. Construction: Construction of a light rail project entails relatively less use of heavy equipment compared to other rail projects. Nevertheless, the construction activities of the project would generate perceptible vibration levels. Potential construction vibration impacts are assessed separately from operational vibration impacts.


2.0 REGULATORY FRAMEWORK

Noise and vibration impact criteria that apply to this project are described below. As part of the regulatory framework discussion, typical terminology for noise and vibration are used; for more information on the basics of noise and vibration, including terminology, refer to Appendix A.

2.1 STATE AND LOCAL NOISE AND VIBRATION LIMITS

No state statutes related to noise and vibration apply to the operation of the proposed project. The FTA Noise and Vibration guidelines are used for this evaluation. The FTA guidelines, analysis methods and criteria reflect the best available research on the topic. Construction noise limits are discussed in Section 6.1 as part of the construction noise impact assessment.

2.2 FTA NOISE IMPACT CRITERIA

The noise impact criteria for use on federally financed transit projects are defined in the FTA Noise and Vibration Impact Assessment guidance manual (2006; also referred to as FTA Guidance Manual). The FTA criteria are based on the best available research on community response to noise. This research shows that characterizing the overall noise environment using measures of noise exposure provides the best correlation with human annoyance. Noise exposure characterizes noise levels over a period of time. FTA provides different thresholds for different land uses. Table 3 lists the three FTA land-use categories and the applicable noise metric for each category. For Category 2 land uses (residential areas where people sleep), noise exposure is characterized using Ldn. In calculating Ldn, noise generated during nighttime hours is more heavily weighted than daytime noise to reflect residents’ greater sensitivity to noise during those hours. For Category 1 and Category 3 land uses (areas with primarily daytime use), noise exposure is characterized using the peak hour Leq, which is a time-averaged sound level over the noisiest hour of transit-related activity. Appendix A provides background information on the Ldn and Leq noise descriptors.


TABLE 3: FTA LAND USE CATEGORIES AND NOISE METRICS

Land Use Category

Noise Metric (dBA) Description of Land Use Category

1 Outdoor Leq(h)a

A tract of land where quiet is an essential element of the intended purpose. This category includes lands set aside for serenity and quiet and such land uses as outdoor amphitheaters and concert pavilions, as well as national historic landmarks with significant outdoor use. Also included are recording studios and concert halls.

2 Outdoor Ldn Residences and buildings in which people sleep. This category includes homes, hospitals and hotels, where a nighttime sensitivity to noise is assumed to be of utmost importance.

3 Outdoor Leq(h)a

Institutional land uses with primarily daytime and evening use. This category includes schools, libraries and churches, where it is important to avoid interference with such activities as speech, meditation and concentration on reading material. Places for meditation or study associated with cemeteries, monuments, museums, campgrounds and recreational facilities can also be considered to be in this category. Certain historical sites and parks are also included.

Source: Federal Transit Administration (2006) a Leq for the noisiest hour of transit-related activity during hours of noise sensitivity.

The FTA noise impact threshold is a sliding scale based on existing noise exposure and land use of sensitive receivers. The basic concept of the FTA noise impact criteria is that more project noise is allowed in areas where existing noise is higher. However, in areas where existing noise exposure is higher, the allowable increase above the existing noise exposure decreases. For example, in an area with an existing noise level of 55 dBA, the allowable increase in noise level is 3 dBA, resulting in a total future noise level of 58 dBA. For an area with an existing noise level of 60 dBA, the allowable increase in noise level is only 2 dBA, resulting in a total future noise level of 62 dBA. FTA defines two levels of noise impact: moderate and severe. In accordance with the FTA Guidance Manual, mitigation to reduce noise levels must be considered for both degrees of impact. The manual also states that for severe impacts “… there is a presumption by FTA that mitigation is incorporated into the project unless there are truly extenuating circumstances which prevent it.” In considering mitigation for severe impacts in this study, the goal is to reduce noise levels to below the moderate impact threshold. FTA allows more discretion for mitigation of moderate impacts based on the consideration of factors including cost, number of sensitive receivers affected, community views, the amount by which the predicted levels exceed the impact threshold and the sensitivity of the affected receivers. For the South Central Light Rail Extension Project, mitigation is recommended for all moderate and severe noise impacts, except where moderate impacts are less than 1 dB. The FTA noise impact criteria are given in tabular format in Table 4 with the thresholds rounded off to the nearest decibel. The criteria are shown graphically in Figure 3 for the different categories of land use along with an example of how the criteria are applied. The two graphs on the left are for nonresidential land uses where Leq(h) represents the noise exposure metric, and the top right graph is for residential land uses where Ldn represents the noise exposure metric. As shown in Figure 3, the impact threshold is a Noise and Vibration Technical Report 14 March 2016 Environmental Assessment South Central Light Rail Extension

sliding scale and it typically increases with an increase in existing noise exposure. The existing noise appears on the horizontal axis, and the amount of new noise that the project can create is on the vertical axis. The lower curve (blue) defines the threshold for moderate impact and the upper curve (red) defines the threshold for severe impact. The sample graph located in the bottom right corner of Figure 3 may help clarify the concept of a sliding scale for noise impact. Assume that the existing noise has been measured at 60 dBA Ldn. This is the total noise from all existing noise sources over a 24-hour period: traffic, aircraft, lawnmowers, children playing, birds chirping, etc. Starting at 60 dBA on the horizontal axis, follow the vertical line up to where it intersects the moderate and severe impact curves. Then refer to the left axis to see the impact thresholds. An existing noise of 60 dBA Ldn gives thresholds of 57.8 dBA Ldn for moderate impact and 63.4 dBA Ldn for severe impact. Note that the values are measured in tenths of a decibel to avoid confusion from rounding off; in reality, one cannot perceive a tenth of a decibel change in sound level. Note that the curves in Figure 3 are defined in terms of project-only noise (on the vertical axes) and the existing noise (on the horizontal axes). The project-only noise is the noise introduced into the environment by the project; it is not the future noise levels with the project. The project-only noise does not include noise from existing noise sources in the area that won’t change as a result of the project such as automobile traffic and airplanes. For TPSS units, an additional noise limit is applied that is more stringent than the FTA noise impact criteria to ensure no impacts are overlooked. A noise impact is indicated when the predicted TPSS nighttime Leq noise level exceeds the existing nighttime Leq minus 5 decibels at residential receivers. The criteria do not differentiate between moderate and severe impacts. Note that the FTA Guidance Manual does not include separate thresholds for TPSS noise. Noise level goals that are more stringent than the FTA guidance criteria are often applied. By setting the impact limit to 5 dB below the existing nighttime noise, this ensures that a TPSS unit will add less than 1 dB to the background noise during typical sleeping hours. A 1-dB change is generally considered to be imperceptible; U.S. Department of Transportation (U.S. DOT) publications state that a 3-dB change is barely perceptible, so a change of 1 dB is usually ignored. The criteria applied to the South Central Light Rail Extension as described above have been used on other FTA-reviewed projects such as the Central Mesa Light Rail Extension and Tempe Streetcar.

TABLE 4: FTA NOISE IMPACT CRITERIA Existing Noise

Exposure, Leq or Ldn

Project Noise Exposure Impact Thresholds, Leq or Ldn (dBA)

Category 1 or 2 Land Uses Category 3 Land Uses

Moderate Impact Moderate Impact Severe Impact Moderate Impact Severe Impact <43 Ambient+10 Ambient+15 Ambient+15 Ambient+20 43 52 58 57 63 44 52 58 57 63 45 52 58 57 63 46 53 59 58 64


TABLE 4: FTA NOISE IMPACT CRITERIA Existing Noise

Exposure, Leq or Ldn

Project Noise Exposure Impact Thresholds, Leq or Ldn (dBA)

Category 1 or 2 Land Uses Category 3 Land Uses

Moderate Impact Moderate Impact Severe Impact Moderate Impact Severe Impact 47 53 59 58 64 48 53 59 58 64 49 54 59 59 64 50 54 59 59 64 51 54 60 59 65 52 55 60 60 65 53 54 60 60 65 54 55 61 60 66 55 56 61 61 66 56 56 62 61 67 57 57 62 62 67 58 57 62 62 67 59 58 63 63 68 60 58 63 63 68 61 59 64 64 69 62 59 64 64 69 63 60 65 65 70 64 61 65 66 70 65 61 66 66 71 66 62 67 67 72 67 63 67 68 72 68 63 68 68 73 69 64 69 69 74 70 65 69 70 74 71 65 70 71 75 72 66 71 71 76 73 66 71 71 76 74 66 72 71 77 75 66 73 71 78 76 66 74 71 79 77 66 74 71 79

>77 66 75 71 80 Source: Federal Transit Administration (2006) Note: Ldn is used for land uses where nighttime sensitivity is a factor; maximum 1 hour Leq is used for land uses involving only daytime activities.


FIGURE 3: FTA NOISE IMPACT CRITERIA


2.3 FTA IMPACT CRITERIA FOR GROUNDBORNE VIBRATION

The potential adverse effects of rail transit groundborne vibration include perceptible building vibration, rattle noises, reradiated noise (groundborne noise) and cosmetic or structural damage to buildings. The vibration caused by modern light rail operations is well below what is considered necessary to damage buildings. Therefore, the criteria for building vibration caused by transit operations are only concerned with potential annoyance of building occupants. The FTA vibration impact criteria are based on the maximum indoor vibration level as a train passes. There are no impact criteria for outdoor spaces such as parks because outdoor groundborne vibration does not provoke the same adverse human reaction as indoor vibration. The FTA Guidance Manual (2006) provides two sets of criteria: one based on the overall vibration velocity level for use in General Vibration Impact Assessments, shown in Table 5, and one based on the maximum vibration level in any 1/3 octave band (the band maximum level) for use with a Detailed Vibration Assessment. A 1/3 octave band is a range of frequencies, and each 1/3 octave band is referred to by the center frequency in that band. Predicted vibration on a 1/3 octave band basis allows vibration mitigation to be designed for the frequency range in which it will be most effective. This study uses the Detailed Vibration Assessment criteria. The criteria for use with Detailed Vibration Assessments are shown in Figure 4. The predicted vibration levels are compared to the criteria curves shown in Figure 4 to determine whether there is impact and the frequency range over which vibration mitigation is required. Impact is identified when the predicted vibration velocity in any 1/3 octave band exceeds the applicable curve. The VC-A through VC-E curves are used to specify acceptable vibration limits for sensitive equipment such as electron microscopes. The “Residential (Night)” curve is applied to residential land uses, similar to the Category 2 land use defined for the noise analysis. The “Residential (Day)” curve is applied to institutional land uses with primarily daytime use such as schools, libraries and churches, and is similar to the Category 3 land use defined for the noise analysis. Table 6 provides a brief description of each of the curves shown in Figure 4. The use of the criteria is illustrated by the example vibration spectra (the dashed blue line) shown in Figure 4. The maximum example level exceeds the “Residential (Night)” curve in the 50 and 63 Hz 1/3 octave bands. For this example, impact would be predicted for residential land uses, and vibration mitigation would be evaluated. However, no impact would be predicted for institutional land uses, because the example spectra does not exceed the “Residential (Day)” curve in any 1/3 octave band. Some buildings, such as concert halls, recording studios and theaters, can be very sensitive to vibration but are not associated with the curves in Figure 4. Given the sensitivity of these buildings, they usually warrant special attention during the environmental evaluation of a transit project. Table 7 gives the FTA criteria for acceptable levels of groundborne vibration and groundborne noise for various categories of special buildings. These criteria are for limits on the overall vibration or noise levels, not the 1/3 octave band spectra. No buildings along the main corridor alignment are considered a special land use.


TABLE 5: FTA GROUNDBORNE VIBRATION AND GROUNDBORNE NOISE IMPACT CRITERIA

Land Use Category

Groundborne Vibration (VdB re 1 micro-inch/second)

Groundborne Noise Impact Levels (dBA re 20 micro

Pascals)

Freq

uent

Ev

enta

Occ

asio

nal

Even

tb

Infr

eque

nt

Even

tc

Freq

uent

Ev

enta

Occ

asio

nal

Even

tb

Infr

eque

nt

Even

tc

Category 1: Buildings where vibration would interfere with interior operations. Typically land uses include vibration-sensitive research and manufacturing, hospitals with vibration-sensitive equipment and university research operations

65d 65d 65d N/Ad N/Ad N/Ad

Category 2: Residences and buildings where people normally sleep

72 75 80 35 38 43

Category 3: Institutional land uses with primarily daytime use

75 78 83 40 43 48

Source: Federal Transit Administration (2006) a Frequent events defined as more than 70 vibration events per day. b Occasional events are defined as between 30 and 70 events per day. c Infrequent events are defined as less than 30 events per day. d This criterion limit is based on levels that are acceptable for most moderately sensitive equipment such as optical microscopes.


FIGURE 4: FTA CRITERIA FOR DETAILED VIBRATION ANALYSIS


TABLE 6: INTERPRETATION OF VIBRATION CRITERIA FOR DETAILED ANALYSIS

Criterion Curve Max Lva (VdB) Description of Uses

Workshop 90 Distinctly feelable vibration. Appropriate to workshops and nonsensitive areas.

Office 84 Feelable vibration. Appropriate to offices and nonsensitive areas.

Residential Day 78 Barely feelable vibration. Adequate for computer equipment and low-power optical microscopes (up to 20X).

Residential Night, Operating Rooms 72

Vibration not feelable, but groundborne noise may be audible inside quiet rooms. Suitable for medium-power optical microscopes (100X) and other equipment of low sensitivity.

VC-A 66 Adequate for medium- to high-power optical microscopes (400X), microbalances, optical balances and similar specialized equipment.

VC-B 60 Adequate for high-power optical microscopes (1000X), inspection and lithography equipment to 3 micron line widths.

VC-C 54 Appropriate for most lithography and inspection equipment to 1 micron detail size.

VC-D 48 Suitable in most instances for the most demanding equipment, including electron microscopes operating to the limits of their capability.

VC-E 42 The most demanding criterion for extremely vibration-sensitive equipment.

Source: Federal Transit Administration (2006), Table 8-3 a Maximum allowed vibration velocity in any 1/3 octave band over the range of 8 to 80 Hz.

TABLE 7: GROUNDBORNE NOISE AND VIBRATION IMPACT CRITERIA FOR SPECIAL BUILDINGS

Location Groundborne

Vibration Impact Levels (VdB re 1 micro-inch/second)

Groundborne Noise Impact Levels

(dBA re 20 micro Pascals) Concert halls 65 25 TV studios 65 25 Recording studios 65 25 Auditoriums 72 30 Theaters 72 35 Source: Federal Transit Administration (2006), Table 8-2


The FTA Guidance Manual also presents criteria for assessing groundborne noise impact for the sensitive land use categories other than the special buildings. Groundborne noise is caused by the vibration of room surfaces radiating sound waves. When audible groundborne noise occurs, it sounds like a low-frequency rumble. When the tracks are above ground, the groundborne noise is usually masked by the normal airborne noise radiated from the rails and it is not necessary to assess impact from groundborne noise. However, for buildings that have no windows facing the rail, or have interior spaces where airborne noise does not penetrate, groundborne noise may be a factor. Measurements discussed in Section 3.4 indicate that there is efficient propagation of vibration at 100 Hz as well as high force density level at 100 Hz. This is a controlling frequency for LRV groundborne noise; therefore, a close analysis of groundborne noise will be included in this analysis. Table 5 shows the impact limits for groundborne noise for receivers. The limits for groundborne noise are based on overall A-weighted levels, in contrast to groundborne vibration, which has limits based on 1/3 octave bands. Category 1 receivers have no defined limit; the limits for these receivers are based on the specific needs such as specific equipment limits for microscopes. Category 2 receivers have a limit of 35 dBA, and Category 3 receivers have a limit of 40 dBA. As noted above, it is possible that airborne noise will dominate the noise at a receptor, in which case the FTA limits may be more stringent than is necessary. Therefore, it is appropriate to compare the predicted groundborne noise levels to predicted indoor noise levels. Impact will be considered if the A-weighted groundborne noise exceeds the A-weighted airborne noise for a single LRV passby. The FTA vibration thresholds do not specifically account for existing vibration. Although there are substantial volumes of vehicular traffic including buses and trucks in the project area, it is relatively rare that rubber-tired vehicles will generate perceptible ground vibration unless there are irregularities in the roadway surface such as potholes or wide expansion joints. There are also existing light rail operations, as well as freight rail, in the Downtown area. Note that historic structures that do not fall into the FTA land use categories are not included in the assessment for vibration impact from light rail operations. The vibration impact thresholds are based on annoyance, and the primary concern for historic structures is the risk of damage. The recommended limit in the FTA Guidance Manual for buildings extremely susceptible to damage is 90 VdB, which is 18 decibels higher than the limit for Category 2 (residential) land uses. Vibration from light rail operations will be well below the limit for buildings extremely susceptible to damage at all historic resources.


3.0 NOISE AND VIBRATION METHODOLOGY

3.1 NOISE ASSESSMENT APPROACH

The detailed assessment for noise included the following steps: 1. Identify sensitive receivers. Noise-sensitive land uses along the corridor were

identified first using aerial photography. Field visits were then conducted to confirm land uses and gather additional relevant information, such as the presence of second stories, land use in the first floor of mixed use buildings and the presence of any intervening structures. Sensitive receivers were grouped together in clusters, where appropriate, based on their location relative to the tracks and land use type. Predictions for each cluster are based on the distance from the proposed project to the closest sensitive receiver. Appendix F details the cluster locations used in the assessment.

2. Determine 2015 conditions. As discussed in Section 4.0 and Appendix E, existing noise levels were measured along the project corridor at four long-term sites for 24 hours, and at ten short-term sites ranging from 20 minutes to 1 hour. The measurements were used to estimate the existing Ldn and daytime Leq at all of the sensitive receiver clusters.

3. Develop prediction models. The noise prediction models are based on formulas provided in the FTA Guidance Manual and noise measurements of the Valley Metro Starter Line. The predictions of light rail noise are based on the forecasted future number of daily trains and the distribution of these trains throughout the day (early morning, daytime and nighttime); the distance from the tracks; addition of special trackwork; the train speed; the presence of walls, berms, or other structures that reduce noise levels and other site-specific conditions. The predictions also include noise from train bells at stations and signaled intersections, crossing gate bells and TPSS units. A model was also developed to do separate predictions of noise from TPSS units for purposes of comparing noise levels to nighttime noise near residential receivers.

4. Estimate future noise levels at the representative receivers. The prediction models were used to predict noise levels from train operations at all clusters of sensitive receivers in the South Central Light Rail Extension corridor. The predictions were compared to the applicable FTA impact thresholds to identify potential noise impacts.

5. Evaluate mitigation options. Mitigation options were evaluated for all locations where the predicted noise levels exceed the FTA impact thresholds.

3.2 NOISE PREDICTION MODEL

This section describes the models that were used to predict noise related to the light rail operations.

3.2.1 Noise from Train Operations

The noise prediction model follows the noise impact assessment methodology for detailed noise predictions presented in the FTA Guidance Manual and incorporates Noise and Vibration Technical Report 23 March 2016 Environmental Assessment South Central Light Rail Extension

assumptions on operating conditions specific to the project, including speeds, vehicle type and train frequencies. For well-maintained light rail systems, the wheel-rail noise dominates above 20 mph and the noise from propulsion motors, air conditioning and other auxiliary equipment on the vehicles dominate below 20 mph. The noise predictions for this analysis are based on reference noise level measurements from the embedded sections of the Valley Metro Light Rail Starter Line with operating speeds the same or similar to the proposed light rail alignment (refer to Appendix C for further discussion on the reference data used for the noise predictions). The reference levels used for this analysis are:

• Maximum sound level (Lmax) of a two-car train operating at 35 mph on embedded track at a distance of 50 feet: 77 dBA

• Train speed: 25 to 35 mph (varies by section)

• Train length: Two cars for all trains. Three-car trains are possible during high demand; these would be operated during daytime and evening hours, which would have minimal effect on noise predictions. Therefore, a two-car consist has been used as the normal train configuration for all noise modeling.

• Noise amplification from crossover frogs: +10 dB at a distance of 35 feet (adjusted by distance)

• Note that wheel squeal (noise amplification of +10 dB for any curve with radius less than 600 feet) was not included in any of the predictions; LRVs would travel on low-radius curves during nonrevenue operations only, and it is assumed that proper friction modification or lubrication would be applied such that wheel squeal is not an issue.

• Note that it is assumed that the rails and wheels would be maintained in a state of good repair such that noise from rail corrugations and wheels flats would be minimized, and additional noise for these elements is not included in the predictions.

These values were used with formulas included in the FTA Guidance Manual to predict the noise levels at each cluster of sensitive receivers. The principal formulas are: Relationship between Lmax and the Sound Exposure Level (SEL):

( )( ) 3.32sin2log10max +

+×−= aa

lengthspeedLSEL

where: speed = Velocity in mph length = Length of vehicle (reference is two-car LRV = 190 feet) α = tan-1(length/2y), where y is the distance from receiver to track centerline


Change in sound level with speed:

=∆

1

2log20 speedspeedSEL

where: 1speed = Reference speed (35 mph)

2speed = Predicted speed (25 to 35 mph, varies by section) SEL∆ = Change in SEL for speed change from speed1 to speed2

The above speed relationship is valid for train speeds higher than 20 mph. Calculation of Ldn and hourly Leq from SEL:

𝐿𝐿𝐿𝐿𝐿𝐿 = 𝑆𝑆𝑆𝑆𝐿𝐿𝑟𝑟𝑟𝑟𝑟𝑟 + 10 log(𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 + 𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 × 10) − 10 log �𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑟𝑟𝑟𝑟𝑟𝑟� � − 49.4

𝐿𝐿𝐿𝐿𝐿𝐿(ℎ𝑜𝑜𝑜𝑜𝑜𝑜) = 𝑆𝑆𝑆𝑆𝐿𝐿𝑟𝑟𝑟𝑟𝑟𝑟 + 10 log(𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇) − 10 log �𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑟𝑟𝑟𝑟𝑟𝑟� � − 35.6

where: NTrainDAY = Number of trains during daytime hours (7 a.m. to 10 p.m.) NTrainNIGHT = Number of trains during nighttime hours (10 p.m. to 7 a.m.) NTrainHOUR = Number of trains during 1 hour Dist = Distance from train tracks to the sensitive receiver Distref = Reference distance (50 feet)

The proposed operating schedule is shown in Table 8. The predicted noise levels in Section 5.0 include train operations between 5 a.m. and 3 a.m. to reflect worst-case noise conditions. Also included in the noise prediction calculations are adjustments for ground type and shielding due to buildings (for receivers beyond the first row) as described in the FTA Guidance Manual.

TABLE 8: PROPOSED TRAIN OPERATING SCHEDULE Hours Frequency

5 a.m.–6 a.m. 20 minutes 6 a.m.–7 p.m. 12 minutes 7 p.m.–12 a.m. 20 minutes

12 a.m.–3 a.m. 20 minutes (Friday and Saturday only)


3.2.2 Prediction Model, Noise from Audible Warnings

3.2.2.1 Train Bells

Bells would be installed at both ends of the trains and may be activated at the front or both front and rear ends. The noise from bells is modeled based on the bell sound level for the Valley Metro light rail vehicles and the assumption that the bells are line sound sources (moving). The bell reference sound level is assumed to be a maximum sound level (Lmax) of 80 dBA at a distance of 50 feet from the bell. The train bells are included in the analysis for two reasons: (1) when stopping and starting from the train stations and (2) at stoplights when the train starts after stopping for the signals. A reasonable assumption is that approximately half of the trains would sound the bell at signaled intersections since the bells would only be sounded when the signal requires the train to stop at an intersection. The bell noise model also assumes that the bells would be sounded by all trains when stopping and starting from train stations. The principal formulas used for this analysis are: Relationship between Lmax and SEL:

[ ]TLSEL log10max ×+= where: T = Duration of the bell noise (seconds/ring * # rings; T = 2 for this study)

Calculation of Ldn and hourly Leq from SEL:

𝐿𝐿𝐿𝐿𝐿𝐿 = 𝑆𝑆𝑆𝑆𝐿𝐿𝐵𝐵𝑟𝑟𝐵𝐵𝐵𝐵 + 10 log(𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 + 𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑥𝑥10) − 10 log �𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑟𝑟𝑟𝑟𝑟𝑟� � − 49.4

𝐿𝐿𝐿𝐿𝐿𝐿(ℎ𝑜𝑜𝑜𝑜𝑜𝑜) = 𝑆𝑆𝑆𝑆𝐿𝐿𝐵𝐵𝑟𝑟𝐵𝐵𝐵𝐵 + 10 log(𝑁𝑁𝑇𝑇𝑟𝑟𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇) − 10 log �𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑟𝑟𝑟𝑟𝑟𝑟� � − 35.6

where: NTrainDAY = Number of trains sounding bell during daytime hours NTrainNIGHT = Number of trains sounding bell during nighttime hours NTrainHOUR = Number of trains sounding bell during 1 hour Dist = Distance from the bell to the sensitive receiver Distref = Reference distance (50 feet)

3.2.2.2 Crossing Bells

Where crossing gates are installed, it is assumed that bells ring for 30 seconds, which includes only the time for warning, arms going down and arms going up (assumes bells are not sounded while down and the train is passing through). The assumed crossing bell reference level is 73 dBA maximum sound level (Lmax) at a distance of 50 feet from the bell (extracted from FTA Guidance Manual and equivalent to 87 dBA at 10 feet; note that the American Railway Engineering and Maintenance-of-Way Association (AREMA) C&S Manual, Part 3.2.61 [AREMA 2010] states that a soft tone bell should produce a sound level no more than 85 dBA and no less than 75 dBA at a distance of 10 feet). The Noise and Vibration Technical Report 26 March 2016 Environmental Assessment South Central Light Rail Extension

same formulas apply as for train bells, with the exception of the distance correction. The crossing bells are assumed to be a point source rather than a line source, so the multiplier for the distance correction is 20 instead of 10 in the Ldn and Leq equations. So rather than a distance correction of “-10log(Dist/Dist_ref)”, the correction is “-20log(Dist/Dist_ref)”.

3.2.3 Ancillary Equipment

The only ancillary equipment expected to have the potential of causing noise impacts are the TPSS units. The primary noise sources from the TPSS units are the transformer hum and noise from cooling systems. On most modern TPSS units the transformer hum is minimal, so only the ventilation and cooling system has potential to cause noise impacts. A recent noise measurement of a TPSS unit used in a residential area along the Los Angeles Metro Gold Line showed that the ventilation fan generated a sound level of 51 dBA at a distance of 40 feet from the fan, which is equivalent to an Leq of 49 dBA at a distance of 50 feet (the measurement was not done at 50 feet because of obstructions). The measured noise level is consistent with the limit of 50 dBA at 50 feet from any side of the TPSS that has been included in the purchase specifications for TPSS units on several recently completed light rail systems. It has been assumed that similar units would be used on the South Central Light Rail Extension Project. TPSS units are included two ways in the noise predictions: (1) added to the train noise for all sensitive receivers and (2) examined separately for residential receivers for nighttime hours. For both inclusions, a reference for Leq of 50 dBA at 50 feet is applied. For inclusion in project noise, the TPSS noise is calculated using the reference and assuming continuous operation, then adjusting for distance and other sound propagation effects (ground type and shielding). Then the TPSS noise is combined with the train and bell noise. For the separate nighttime analysis for residential receivers, the TPSS reference level is simply adjusted for distance.

3.2.4 Road Traffic Analysis

Road traffic noise is analyzed using the Federal Highway Administration (FHWA) Traffic Noise Model (TNM). Three analyses are conducted and are described further in Section 5.0. For these analyses, each lane is modeled as a separate TNM roadway object for the most precise noise source placement as possible, predicted Build and No-Build traffic volumes are applied and posted speeds are applied. In addition, bus schedules and planned bus changes attributable to the project for peak hour operations are included in the model. These analyses were done separately from the operational light rail noise analysis, which is a typical first step to determine if noise from roadway and bus changes needs to be included in potential noise impact predictions. (Note that since the effects from these changes were determined to be minimal, they were not included in the operational noise impact predictions.) Noise and Vibration Technical Report 27 March 2016 Environmental Assessment South Central Light Rail Extension

3.2.5 Park-and-Ride Analysis

Noise from park-and-ride lots is analyzed using steps outlined in the FTA guidance. The following calculation is used:

𝐿𝐿𝐿𝐿𝐿𝐿(ℎ𝑜𝑜𝑜𝑜𝑜𝑜) = 𝑆𝑆𝑆𝑆𝐿𝐿𝑝𝑝𝑇𝑇𝑟𝑟𝑝𝑝−𝑇𝑇𝑇𝑇𝑎𝑎−𝑟𝑟𝑇𝑇𝑎𝑎𝑟𝑟 + 𝐶𝐶𝑇𝑇 − 35.6

where: SELpark-and-ride = Reference level of 92 dBA at 50 feet (this is the FTA reference level for a parking garage, which considers automobiles only; the reference for FTA park-and-ride lots is intended for buses and assumes both automobiles and buses are present) CN = 10*log(# parking spaces / 1000).

Note that for the parking lot near the proposed Baseline Road station, the number of parking spaces is adjusted according to proximity to different portions of the large, T-shaped lot. Included in the number of spaces are those within a 125-foot radius (FTA screening distance for parking lots) and the estimated number of vehicles that would need to pass by a receiver in order to reach other parts of the parking lot. The calculated lot noise is then compared to existing noise. If far below, no further consideration is warranted. If within about 10 dB of the existing noise, the predicted lot noise is combined with other project noise (train operations, TPSS units) to determine whether the combined level exceeds the FTA impact criteria. To convert the Leq values to Ldn, it is assumed that a majority of the lot noise would be between the hours of 5 a.m. and 9 a.m. and between 3 p.m. and 7 p.m., the typical use for commuters.

3.3 VIBRATION ASSESSMENT APPROACH

The detailed assessments for vibration included the following steps: 1. Identify sensitive receivers. Vibration-sensitive land uses along the corridor were

identified using the same procedure as the noise analysis. Sensitive receivers were grouped in clusters based on their location relative to the tracks and land use type. The residential land use clusters were the same for both noise and vibration assessments. Predictions for each cluster are based on the distance from the proposed project to the closest sensitive receiver. Appendix F details the cluster locations used in the assessment. The noise-sensitive institutional land uses are also vibration-sensitive with the exception of open spaces such as parks that are not considered vibration-sensitive land uses. The FTA Guidance Manual does identify vibration-sensitive land uses that are not noise sensitive, such as research laboratories with vibration-sensitive equipment. However, no such land uses exist within the project study area.

2. Develop prediction models. The vibration prediction models are based on the force density level (FDL) measurements made on the Valley Metro Starter Line by ATS Consulting in 2009, and by vibration propagation tests at representative sites along the South Central corridor spaced approximately 2 miles apart or less. The vibration prediction models are based on the FTA Guidance Manual’s detailed vibration assessment methodology.


3. Estimate future vibration levels at the representative receivers. The prediction

models were used to predict vibration levels from train operations at all sensitive receivers in the South Central Light Rail Extension corridor. The predictions were compared to the applicable FTA impact thresholds to identify potential vibration impacts.

4. Evaluate mitigation options. Mitigation options were evaluated for all locations where the predicted vibration levels exceed the FTA impact thresholds.

3.4 VIBRATION PREDICTION MODEL

Localized geologic conditions such as soil stiffness, soil layering and depth to bedrock have a strong effect on groundborne vibration. However, it is difficult to obtain information on subsurface conditions in sufficient detail so that computer models can be used to accurately predict ground vibration. As a result, most detailed predictions of ground vibration are based largely on empirical methods that involve measuring vibration propagation in the soil. The predictions of groundborne vibration for this study follow the Detailed Vibration Assessment procedure of the FTA Guidance Manual (2006). This is an entirely empirical method based on testing of the vibration propagation characteristics of the soil in the project corridor and measurements of the vibration characteristics of a similar train vehicle. The quantity derived from propagation tests is referred to as the Line Source Transfer Mobility (LSTM). The LSTM is used with the FDL—a measure of how much vibration energy trains generate—to predict the vibration energy received by the sensitive receivers. The basic relationship used for the vibration predictions is:

Lv = FDL + LSTM

where: Lv = Train vibration velocity measured at the ground surface LSTM = Measured line source transfer mobility FDL = Force density function that characterizes the vibration forces generated by the train and track (All quantities are expressed in decibels using a consistent set of decibel reference values)

To predict impacts, this vibration level (Lv) is combined with receiver-specific adjustments—such as speed, special trackwork, coupling loss, floor amplification and other factors—and compared against the regulatory limits discussed in Section 2.0. These adjustments are discussed in a later section. The FDL used for this project was developed from measurements of trains running on the existing Valley Metro Starter Track. Train vibration and propagation measurements were conducted by ATS in 2009 at 5552 Washington Street, as part of the Mesa Light Rail Environmental Analysis. Follow-up measurements were made at the same location for the Capitol I-10 Environmental Analysis. Appendix B is a summary of the results of the measurements made in both 2009 and 2013.


The LSTM was calculated at four locations that were selected to represent the vibration sensitive receivers along the South Central alignment. The sites were spaced by approximately 2 miles. Measurements were made at outdoor positions only. Figures F-1 to F-11, in Appendix F, show where the vibration sites are located along the alignment. The average LSTM of three of the measured sites along the alignment was used as in the vibration prediction model. The variation in the measured LSTM among sites was factored into the prediction model using a safety factor discussed in Section 3.4.5. The LSTM and FDL are both empirically derived quantities. The methodology used to derive these values for each receiver in the prediction model is discussed in the following subsections. Groundborne noise is predicted by assuming that groundborne vibration and groundborne noise are directly related. Groundborne noise is derived by adding a radiation factor, Krad, and applying an A-weighting:

𝐿𝐿𝐿𝐿 = 𝐿𝐿𝐿𝐿 + 𝐾𝐾𝑜𝑜𝐿𝐿𝐿𝐿 + 𝐾𝐾𝐿𝐿𝐾𝐾𝐷𝐷

For this analysis Krad is set to –5 dB. This is the value recommended in the upcoming version of the FTA Guidance Manual (2006).

3.4.1 Vibration Propagation Test Procedure

The vibration predictions for the South Central Light Rail Extension Project are based on the Detailed Assessment approach recommended in the FTA Guidance Manual. The FTA Detailed Vibration Assessment uses state-of-the-art tools to characterize how localized soil conditions affect the levels of groundborne vibration. A vibration propagation test is conducted to measure how vibration is transmitted from the light rail tracks through the ground and into the foundations of nearby buildings (see Figure 5).

FIGURE 5: SCHEMATIC OF VIBRATION PROPAGATION TEST

The test procedure consists of creating an impact force using a dropped weight and determining the transfer function relationship between the force generated by the dropped weight and the resulting vibration pulse. The impacts using the dropped weight


are performed in a line located as close to the planned track centerline as possible, and vibration sensors are located at several distances from the impact line. Sensors may also be located inside nearby buildings to provide information on the propagation path from the track centerline to the building’s occupied spaces. Vibration propagation tests were performed at four locations in the South Central corridor, each using a line of 11 impact positions at intervals of 15 feet (marked as the line of impacts in Figure 5). The relationship between the exciting force and the resulting vibration level is referred to as the “transfer mobility,” which indicates how easily vibration travels through the earth. Each of the 11 impact positions yields a point-source transfer mobility. Numerically integrating the 11 point-source transfer mobilities yields the LSTM. Each accelerometer yields its own LSTM at a different distance, which can be fit to an LSTM-vs-log (distance) curve to predict LSTM as a function of distance.

3.4.2 Vibration Propagation Test Sites

The four locations for the vibration propagation tests were selected to represent the vibration-sensitive receivers along the South Central corridor. The sites were spaced by approximately 1 to 2 miles. The measurements included transfer mobilities into indoor spaces at four of the locations. The location of sensors and force-impacts at each measurement site is shown in Figures D-5 to D-8 in Appendix D. The details of the vibration propagations sites are discussed below: V-1 Maricopa County Superior Courthouse: This measurement was performed at 101 Madison Street, outside of the Maricopa County Superior Courthouse. The line of impacts was located on the west sidewalk of First Avenue. Sensors were placed outdoors on the walkway just north of the courthouse. The sensors were located at 25, 50, 75, 100, 150 and 200 feet from the impact line. Figure D-5 shows the aerial view of vibration propagation test site V-1. V-2 1020 South Central Avenue: This measurement was performed in a lot located at 1020 South Central Avenue. The impact line was located on the west sidewalk of South Central Avenue. The sensors were mounted at 28, 48, 75, 100 and 125 feet from the impact line. Figure D-6 shows the aerial view of vibration propagation test site V-2. V-3 4216 South Central Avenue: This measurement was performed in an open lot just north of 4216 South Central Avenue. The impact line at this site was located on the west sidewalk of South Central Avenue. Vibration sensors were placed at distances of 25, 37, 50, 75, 100 and 140 feet from the impact line. All sensors were placed on stakes in the ground. Figure D-7 shows the aerial view of vibration propagation test site V-3. V-4 South Mountain Mortuary: This measurement site was located on the east side of South Central Avenue, between Carter Road and Jesse Owens Parkway. The impact line was located on the eastern sidewalk of South Central Avenue. The sensors were placed in the parking lot of the mortuary, located at 25, 37, 50, 75, 100 and 150 feet from the impact line. Figure D-8 shows the aerial view of vibration propagation test site V-4.


3.4.3 Applying Vibration Propagation Test Results to Prediction Model

The measured LSTMs and coherences for each vibration propagation test site are shown in Appendix D. The LSTMs for each site were used to create best-fit curves of LSTM versus log-distance. The best-fit coefficients are presented in Appendix D. Figure 6 shows graphs of the best-fit LSTM at each measurement site and at varying distances. Below is a summary of the key observations from Figure 6:

• LSTM at three of the test sites has a single peak, broad-shaped, in the 40–50 Hz Bands.

• The LSTM at Site V-2 has a peak in the 20 Hz Band.

• The LSTM at Site V-3 is about 5 dB higher than at the other sites in the peak bands of 40 and 50 Hz. This difference is more pronounced at farther distances.

• The LSTM at Site V-4 is higher than the others at frequencies below 16 Hz. This is not a crucial frequency range for predicting impact.

• The standard deviation among LSTM values at 40 Hz is about 3 dB. The average standard deviation among all bands is closer to 5 dB.

• The LSTMs tend to fall off with distance at similar rates across test sites.

Figure 7 shows the maximum, average and minimum LSTM for five setback distances. The graphs also show the energy average of Sites V-1, V-2 and V-4. These plots illustrate the distribution of measured values across the alignment and provide the basis for the calculation of the final best-fit LSTM curve coefficients. The final LSTM used to define the best-fit curves for this analysis will be the average of Sites V-1, V-2 and V-4. The results from Site V-3 are being excluded because of the high outlying values in the 40 Hz band. It is likely that this is a site-specific trait that may have to do with the nearby buildings or unknown underground utilities. To construct the final LSTM curve used in the prediction model, the average LSTM for each distance (shown in Figure 7) was incorporated into a best-fit curve for LSTM-vs-log(distance) for each 1/3 octave band. The best fit coefficients are shown in Table 9. The equation used for the fit is as follows:

LSTM(d) = A + B*log(d) + C*log(d)2 where: LSTM = Line Source Transfer Mobility in dB re 1 (µin/sec)/(lb/ft1/2) d = Distance in feet

As shown in Table 9, the C term described above is not used. The vibration propagation data show that it decreases by the log with distance.


FIGURE 6: BEST-FIT LSTM AT ALL SITES


FIGURE 7: BEST-FIT LSTM – MAXIMUM, MINIMUM AND AVERAGE OF ALL SITES


TABLE 9: LSTM COEFFICIENTS FOR PREDICTION MODEL Frequency A B C

6.3 18.1 –6.8 — 8 23.8 –7.7 — 10 31.6 –8.3 — 12.5 32.3 –6.1 — 16 38.2 –6.3 — 20 48.6 –8.8 — 25 54.1 –10.0 — 31.5 62.2 –14.2 — 40 71.1 –19.5 — 50 83.6 –27.3 — 63 82.6 –29.0 — 80 77.8 –29.0 — 100 78.0 –32.7 — 125 85.2 –39.8 — 160 92.7 –47.0 — 200 87.4 –48.1 — 250 75.5 –44.6 — 315 61.3 –37.5 —

3.4.4 FDL

FDL is derived by measuring Lv and LSTM at a site where light rail is already in operation and calculating the FDL using the equation: Lv = FDL + LSTM. The project uses an FDL measurement from the Valley Metro Starter Line. The FDL of the Starter Line was measured in 2009 as part of the Mesa Project (Valley Metro 2010). The results of the FDL measurements at this site are shown in Figure 8 for LRV speeds of 30 mph. Details of the FDL tests and results are in Appendix B. The FDL has a peak at 80 Hz of about 40 dB. This is 10 dB higher than a typical light rail, as suggested by the FTA Guidance Manual. As discussed in Appendix B, a low FDL can be maintained in light rail systems through a program that manages optimal wheel-rail profile and proactively eliminates potential for wheel deformations.


FIGURE 8: LIGHT RAIL FORCE DENSITY LEVEL AT 30 MPH

3.4.5 Adjustments of Lv for Prediction Model

After determining the FDL and LSTM discussed in the previous sections, the following adjustments were incorporated into the prediction model to estimate vibration levels in occupied spaces of buildings:

• Speed Adjustment: The Washington Street FDL represents a train traveling at 30 mph. Adjustments to other speeds is made using 15*log(speed).

• Special Trackwork: The additional vibration at special trackwork was accounted for by adding 10 decibels to the predicted vibration levels when the special trackwork frog would be located less than 50 feet from a sensitive receiver. At distances greater than 50 feet, the additional vibration from crossovers is assumed to decay at a rate of 15*log(dist) (decay rate based on measured vibration propagation).

• Theoretical Coupling Loss and Floor Amplification: For lightweight wood-frame structures, the FTA Guidance Manual suggests +6 dB for floor amplification and –2 dB per floor for floor-to-floor attenuation up to five floors above grade, as well as a –5 dB adjustment for coupling loss. Combining the adjustment factors for a wood-frame structure such as a residence, there is −5 dB for the coupling loss, +6 dB for floor amplification and an additional −1 to −2 dB for each floor above the grade level. This leads to a net adjustment of between –1 to +1 dB for the vibration inside a typical residence. Therefore, no adjustment is applied to account for coupling loss and floor amplification in the prediction model for small single-story residences. For large masonry buildings, the FTA Guidance Manual suggests a –10 dB adjustment for coupling loss. This adjustment has been used at most Downtown area receivers, including multifamily residences and courthouses.


• Measured Building Amplification and Safety Factor: It is not feasible to consider

each receiver individually without a considerable amount of additional measurements. Therefore, to account for potential amplification effects from buildings and other possible sources of error in the predictions, a safety factor of +3 dB was added to each 1/3 octave band. This is a conservative approach, ensuring that in the majority of cases the predicted vibration levels are higher than what would occur after the proposed project is operational.

• Radiation Factor, Krad: The radiation factor is an adjustment to convert from groundborne vibration to sound pressure level. The 2006 FTA Guidance Manual suggests 0 dB for Krad. The upcoming revised FTA Guidance Manual will suggest –5 dB for Krad. In this analysis, –5 dB will be used. The final sound pressure levels will also have an A-weighting applied.

As described in Section 2.3, the groundborne noise will be compared to the predicted level of airborne noise inside each receiver. Impact is predicted if the groundborne noise exceeds the airborne noise. To predict indoor airborne noise levels, the maximum level for a single vehicle passby of 77 dB is adjusted for speed and distance to the exterior of the receiver. An adjustment for shielding from intervening building rows is applied. A sound transmission class (STC) is assumed for each building, which represents the decibel level of outdoor-to-indoor noise attenuation. For single-family residences and other single-story slab on grade buildings, the STC is assumed to be 25. For buildings with no windows facing the alignment and large modern hotels, the STC is assumed to be 35. If the A-weighted groundborne noise is less than the predicted airborne noise, then no impact is predicted for groundborne noise.

3.4.6 Final Vibration Prediction Model

Figure 9 presents the predicted vibration level, Lv, with a +3 VdB safety factor at various distances. Also plotted are two FTA criteria for impact for residential land uses. Figure 9 illustrates how, using this model, residential receivers within 75 feet of the alignment would exceed the FTA Residential (Night) criteria. Only a single 1/3 octave band Lv needs to exceed 72 VdB for the residential receiver to be considered an impact. Note that the FTA criteria for a detailed vibration impact assessment uses the Residential (Night) criteria curve for land uses where people sleep including residences and hotels and the Residential (Day) criteria curve for institutional land uses such as schools and churches.


FIGURE 9: PREDICTED LRV VIBRATION SPECTRUM AT 30 MPH

(Curves include a +3 VdB safety factor)


4.0 AFFECTED ENVIRONMENT

Noise and vibration sensitive receivers were identified using the FTA Guidance Manual’s definitions of noise- and vibration-sensitive land uses. Existing noise-sensitive receivers in the South Central Light Rail Extension corridor consist of many single- and multifamily residences, hotels, schools, courthouses, libraries, religious and cultural churches or institutions, a habitat restoration area and medical facilities. A full list of sensitive receivers can be found in Appendix F; some are individual properties and others are clusters or groups of properties. The list includes those potentially sensitive to train noise and vibration, as well as those potentially sensitive to the TPSS units. The habitat restoration areas, which are outdoor land uses, are not sensitive to vibration and are not included in the vibration analysis. The indoor land uses consist of 815 existing dwelling units (includes high-rise building residences/hotel rooms that are exposed to the alignment) and 27 institutional land uses. Some historic structures in the Downtown area were assessed for potential damage from construction noise, as described further in Section 6.0. A noise and vibration test and measurement program was developed to characterize the ambient noise and vibration in the project area. The noise sites included long-term noise (24-hour) measurements, and short-term noise (20 minutes to 1 hour) measurements throughout the alignment. The vibration test program included vibration propagation tests at four sites as well as ambient vibration measurements. At the vibration propagation test sites, the ambient vibration was measured to verify whether the background vibration was below the test signals. These tests were conducted by ATS between September 8 and 10, 2015. These vibration propagation measurements are documented in Appendix D, and the existing noise and vibration measurements are documented in Appendix E. Maps of test/measurement locations, in relation to sensitive receivers, are shown in Appendix F. Details of the measurements are discussed in the rest of this section.

4.1 2015 CONDITIONS – NOISE

The FTA noise impact analysis is based on the existing ambient noise in the project area. The South Central Light Rail Extension project area has several transportation-related noise sources including vehicular traffic, light rail, freight rail and airplane noise as listed below:

• The primary source of traffic noise is vehicles on Central Avenue, 1st Avenue and I-17, including major intersections.

• On Central and 1st Avenues, noise from freight trains running east/west south of Downtown can be heard. The noise is generated from trains passing by and horns sounding near the grade crossings at 1st Street, 2nd Street, 2nd Avenue and 3rd Avenue.

• Light rail is a noise source Downtown on 1st Avenue, Central Avenue, Washington Street and Jefferson Street. It includes the use of train bells at the traffic lights on 1st Avenue, Central Avenue, Washington Street and Jefferson Street as well as when trains approach and leave the Jefferson Street/1st Avenue station and the Washington Street/Central Avenue station.


• Airplanes are a major noise source north of Elwood Street, extending to the

Downtown area, because this area is below and near the flight path for arrival/departure traffic at Phoenix Sky Harbor International Airport.

The existing ambient noise levels along the project corridor were documented through a series of noise measurements performed at a number of representative sensitive receivers. In 2015, noise measurements were performed by ATS at four long-term sites for a period of 24 hours and at ten short-term sites for durations ranging from 20 minutes to 1 hour. More detailed measurement information is in Appendix E. The results of the noise measurements are summarized in Table 10. Details on noise metrics used in this section and Appendix E can be found in Appendix A. Site labels for noise include a prefix that varies based on the duration of the measurement (LT = long term, ST = short term). Sites with a 24-hour measurement show sound levels for both the Ldn and Leq peak hour metrics, since these sites can represent both residential and institutional sensitive receivers in the area. The details of each measurement site follow. Note that the levels shown in the table have been normalized to a distance of 25 feet from the center of the near traffic lane except where noted; the levels shown in the site descriptions below have not been normalized and represent the exact distance at which the measurements were taken. LT-1: Superior Court of Arizona in Maricopa County – Old Courthouse This long-term measurement was performed by the southeast corner of the courthouse between the building façade and the Jefferson Street/1st Avenue station. Primary noise sources were vehicular traffic on 1st Avenue as well as light rail noise in and around the Jefferson Street/1st Avenue station and planes departing Phoenix Sky Harbor International Airport. Secondary sources include vehicular traffic on Jefferson Street and in the courthouse parking lot as well as pedestrians at the train station. The microphone was 35 feet from the near lane of 1st Avenue. The measured 24-hour Ldn was 68 dBA, and the peak hour Leq was 66 dBA. LT-2: Central Avenue and Buckeye Road – Southeast Corner This long-term measurement was performed on the sidewalk by the southeast corner of the Central Avenue and Buckeye Road intersection. The primary noise sources were vehicular traffic on Central Avenue and planes departing Phoenix Sky Harbor International Airport. Secondary noise sources include vehicular traffic on Buckeye Road. The microphone was 35 feet from the near lane of Central Avenue. The measured 24-hour Ldn was 70 dBA, and the peak hour Leq was 71 dBA. LT-3: Central Avenue and Southgate Avenue – Northeast Corner This long-term measurement was performed on the sidewalk by the northeast corner of the Central Avenue and Southgate Avenue intersection. The primary noise source was vehicular traffic on Central Avenue. Secondary noise sources include vehicular traffic on Southgate Avenue. The microphone was 25 feet from the near lane of Central Avenue. The measured 24-hour Ldn was 72 dBA, and the peak hour Leq was 72 dBA. LT-4: South Mountain Mortuary This long-term measurement was performed by the southwest driveway of the South Mountain Mortuary. The primary noise source was vehicular traffic on Central Avenue. Noise and Vibration Technical Report 40 March 2016 Environmental Assessment South Central Light Rail Extension

Secondary noise sources include vehicular traffic on Carter Road and Jessie Owens Parkway. The microphone was 25 feet from the near lane of Central Avenue. The measured 24-hour Ldn was 74 dBA, and the peak hour Leq was 74 dBA. ST-1: Hotel Palomar This short-term measurement was performed by the northwest corner of the hotel. The primary noise source was vehicular traffic on Central Avenue. Secondary noise sources include vehicular traffic and light rail on Jefferson Street as well as foot traffic crossing Central Avenue and planes departing Phoenix Sky Harbor International Airport. This section of Downtown is pedestrian-friendly. The microphone was 45 feet from the near lane of Central Avenue. The measured 1-hour Leq was 69 dBA. ST-2: 1st Avenue and Sherman Street – Southwest Corner This short-term measurement was performed by the southwest corner of the 1st Avenue and Sherman Street intersection. This site is just north of where 1st Avenue merges with Central Avenue. The primary noise source was vehicular traffic on 1st Avenue as well as planes departing Phoenix Sky Harbor International Airport. Secondary noise sources include vehicular traffic on Central Avenue and Sherman Street. The microphone was 48 feet from the near lane of Central Avenue. The measured 1-hour Leq was 68.6 dBA. ST-3: 1st Street and Durango Street – Northeast Corner This short-term measurement was performed by the northeast corner of the 1st Street and Durango Street intersection. The primary noise sources were vehicular traffic on I-17, 1st Street and Durango Street and planes departing Phoenix Sky Harbor International Airport. Secondary noise sources include vehicular traffic on Central Avenue. A large building was between the microphone and Central Avenue, so the highway noise is more prevalent than the noise from Central Avenue. The microphone was 14 feet from the near lane of Durango Street and 410 feet from I-17. The measured 1-hour Leq was 63.2 dBA. ST-4: Rio Salado Habitat Restoration Area This short-term measurement was performed at the gateway area (by the shade structure) south of the Salt River and just east of Central Avenue. The primary noise sources were vehicular traffic on Central Avenue and planes arriving at Phoenix Sky Harbor International Airport. The microphone was 92 feet from the near lane of Central Avenue. The measured 1-hour Leq was 62.6 dBA. ST-4A: Rio Salado Audubon Center – Building This short-term measurement was performed in line with the building setback of the Rio Salado Audubon Center. The primary noise sources were vehicular traffic on Central Avenue and planes departing Phoenix Sky Harbor International Airport. The microphone was 235 feet from the near lane of Central Avenue. The measured 30-minute Leq was 57 dBA. ST-5: Central Avenue and Cody Drive – Northwest Corner This short-term measurement was performed at the northwest corner of the Central Avenue and Cody Drive intersection. The location is next to a trailer park. The primary


noise source was vehicular traffic on Central Avenue. Secondary noise sources include vehicular traffic on Cody Drive. The microphone was 27 feet from the near lane of Central Avenue. The measured 1-hour Leq was 69 dBA. ST-6: 5425 S. Central Avenue This short-term measurement was performed at the northern edge of a parking lot in front of 5425 S. Central Avenue. The location is a half-block north of Sunland Avenue. The primary noise source was vehicular traffic on Central Avenue. The microphone was 25 feet from the near lane of Central Avenue. The measured 1-hour Leq was 73 dBA. ST-7: Cigna Medical Group This short-term measurement was performed on the sidewalk in front of the Cigna Medical Group building. The primary noise source was vehicular traffic on Central Avenue. The microphone was 25 feet from the near lane of Central Avenue. The measured 1-hour Leq was 71 dBA. ST-8: Saint Catherine of Siena Catholic School This short-term measurement was performed on the northeast corner of the Central Avenue and St. Catherine Avenue intersection. The primary noise source was vehicular traffic on Central Avenue. The secondary noise source was vehicular traffic on St. Catherine Avenue. The microphone was 37.5 feet from the near lane of Central Avenue. The measured 1-hour Leq was 71 dBA. ST-9: Baseline Road between 2nd and 3rd Avenues – North Side This short-term measurement was performed just north of Baseline Road between the 2nd and 3rd Avenue cross streets. The Western Canal passes to the north of the measurement location. The primary noise source was vehicular traffic on Baseline Road. The microphone was 50 feet from the near lane of Baseline Road. The measured 20-minute Leq was 71 dBA. Measurements were taken at this site for the purpose of capturing the existing environment for traffic noise analysis model validation purposes.


TABLE 10: SUMMARY OF EXISTING NOISE MEASUREMENTS

Site Location Date Dur.a Start Time

hh:mm

Dist. from Near

Lane of Adjacent Street, ftb

Peak Hour

Leq at 25 ftc, dBA

Ldn at 25 ftc, dBA

LT-1 Superior Court of Arizona in Maricopa County – Old Courthouse

9/9/15 24-hr 9:00 a.m. 35 68 69

LT-2 Central Ave and Buckeye Rd 9/8/15 24-hr 8:00 p.m. 35 73 72

LT-3 Central Ave and Southgate Ave 9/10/15 24-hr 12:00 p.m. 25 72 72

LT-4 South Mountain Mortuary 9/10/15 24-hr 9:00 a.m. 25 74 74 ST-1 Hotel Palomar 9/8/15 1-hr 5:00 p.m. 45 71 — ST-2 1st Ave and Sherman St 9/9/15 1-hr 4:54 p.m. 48 71 — ST-3 1st St and Durango St 9/9/15 1-hr 6:12 p.m. 14 63d 65e

ST-4 Rio Salado Habitat Restoration Area 9/10/15 30-min 8:25 a.m. 92 68 —

ST-4A Rio Salado Audubon Center – Building 9/11/15 1-hr 6:50 a.m. 235 57f —

ST-5 Central Ave and Cody Dr 9/9/15 1-hr 8:16 a.m. 27 70 — ST-6 5425 S Central Ave 9/11/15 1-hr 7:03 a.m. 25 73 —

ST-7 Cigna Medical Group 9/10/15 1-hr 4:58 p.m. 25 71 —

ST-8 Saint Catherine of Siena Catholic School 9/9/15 1-hr 6:48 a.m. 37.5 72 —

ST-9 Baseline Rd between 2nd and 3rd Ave 9/10/15 20-min 6:50 a.m. 50 73 —

Source: ATS Consulting, 2015 data a Duration of measurement b The distance of the microphone from the centerline of nearest lane of Central Ave, 1st Ave, Durango St and Baseline Rd. c Leq and Ldn levels obtained from noise measurements have been normalized to 25 feet, except where noted, using the correction factor: +10*LOG10(Dist_from_Near_Lane/50). d ST-3 levels are not adjusted for distance. They will be applied to receivers located nearby I-17 whose noise levels are dominated by highway noise instead of noise from Central Ave. e An Ldn value is approximated here based on the Leq value; this was necessary to properly represent 24-hour noise in the area, which was dominated by I-17 traffic noise. The Ldn approximation of Leq(1hr) + 2dB is based on ATS experience. The FTA Guidance Manual recommends a 0 dB adjustment based on Leq(day), but this is most likely overly conservative. f The ST-4A Leq is not adjusted for distance because the Leq will be applied to the receiver it was measured next to.


4.2 2015 CONDITIONS – VIBRATION

The potential adverse effects of light rail groundborne vibration include perceptible building vibration, rattle noises, reradiated noise (groundborne noise) and cosmetic or structural damage to buildings. Existing vibration sources in the project corridor primarily consist of vehicular traffic. Secondary sources in the Downtown area include light rail and freight rail operations and intermittent construction activities. When vehicular traffic causes perceptible vibration, the source usually is traced to potholes, wide expansion joints or other “bumps” in the roadway surface. The FTA assessment procedures for vibration from rail transit projects do not require measurements of existing vibration levels. The criteria for vibration impact are independent of existing vibration levels, except those receivers near the existing rail line. Therefore, in this analysis, existing vibration levels were used only to internally validate the measurement data gathered from the vibration prediction model test sites discussed in Section 3.4.2. The South Central Light Rail Extension Project area has several transportation-related vibration sources including vehicular traffic, light rail and freight rail, as listed below:

• The primary source of traffic vibration is vehicles (including buses) on Central Avenue, 1st Avenue and I-17, including major intersections.

• Freight train vibration on Central and 1st Avenues near the Downtown area involves train passby vibration near the grade crossings at 1st Street, 2nd Street, 2nd Avenue and 3rd Avenue.

• Light rail is a vibration source Downtown on 1st Avenue, Central Avenue, Washington Street and Jefferson Street.

The test locations are described below and can be seen graphically in relation to sensitive receivers in Appendix F. Short-term vibration measurements were taken at many of the short-term noise measurement sites (see Appendix D). Site labels for the short-term sites are designated in orange. Short-term vibration measurements were also taken at the vibration propagation sites (see Appendix D). The results of the existing vibration measurements are summarized in Table 11, showing the energy-average vibration levels for each site at the sensor locations. The details of each measurement site are below: ST-1: Hotel Palomar This short-term measurement was performed by the northwest corner of the hotel. The primary vibration source was vehicular traffic on Central Avenue. Secondary vibration sources include vehicular traffic and light rail on Jefferson Street as well as foot traffic crossing Central Avenue. This section of Downtown is pedestrian-friendly. The accelerometer was 45 feet from the near lane of Central Avenue. The measured vibration was 55 VdB. ST-2: 1st Avenue and Sherman Street This short-term measurement was performed by the southwest corner of the 1st Avenue and Sherman Street intersection. This site is just north of where 1st Avenue merges with Central Avenue. The primary vibration source was vehicular traffic on 1st Avenue. Noise and Vibration Technical Report 44 March 2016 Environmental Assessment South Central Light Rail Extension

Secondary vibration sources include vehicular traffic on Central Avenue and Sherman Street. The accelerometer was 48 feet from the near lane of Central Avenue. The measured vibration was 57 VdB. ST-4: Rio Salado Habitat Restoration Area This short-term measurement was performed at the gateway area (by the shade structure) south of the Salt River and just east of Central Avenue. The primary vibration source was vehicular traffic on Central Avenue. The accelerometer was 75 feet from the near lane of Central Avenue. The measured vibration was 48 VdB. ST-5: Central Avenue and Cody Drive – Northwest Corner This short-term measurement was performed at the northwest corner of the Central Avenue and Cody Drive intersection. The location is next to a trailer park. The primary vibration source was vehicular traffic on Central Avenue. Secondary vibration sources include vehicular traffic on Cody Drive. The accelerometer was 27 feet from the near lane of Central Avenue. The measured vibration was 54 VdB. ST-6: 5425 S. Central Avenue This short-term measurement was performed at the northern edge of a parking lot in front of 5425 S. Central Avenue. The location is a half-block north of Sunland Avenue. The primary vibration source was vehicular traffic on Central Avenue. The accelerometer was 25 feet from the near lane of Central Avenue. The measured vibration was 50 VdB. ST-7: Cigna Medical Group This short-term measurement was performed on the sidewalk in front of the Cigna Medical Group building. The primary vibration source was vehicular traffic on Central Avenue. The accelerometer was 25 feet from the near lane of Central Avenue. The measured vibration was 58 VdB. V-1: Maricopa County Superior Courthouse, South Court Tower This site was also used for vibration propagation testing. See Section 3.4.2 for a detailed site description. Existing vibration levels ranged from 47 to 48 VdB, depending on distance from the road. V-2: 1020 S. Central Avenue This site was also used for vibration propagation testing. See Section 3.4.2 for a detailed site description. Existing vibration levels ranged from 42 to 45 VdB, depending on distance from the road. V-3: 4216 S. Central Avenue This site was also used for vibration propagation testing. See Section 3.4.2 for a detailed site description. Existing vibration levels ranged from 48 to 53 VdB, depending on distance from the road. V-4: South Mountain Mortuary This site was also used for vibration propagation testing. See Section 3.4.2 for a detailed site description. Existing vibration levels ranged from 51 to 55 VdB, depending on distance from the road. Noise and Vibration Technical Report 45 March 2016 Environmental Assessment South Central Light Rail Extension

TABLE 11: SUMMARY OF EXISTING VIBRATION MEASUREMENTS

Site Location Date Dur.a Start Time, hh:mm

Dist. from Near Lane

of Adjacent Street, ftb

Vibration at

Sensor, VdB

ST-1 Hotel Palomar 9/8/15 1-hr 5:00 p.m. 45 55 ST-2 1st Ave and Sherman St 9/9/15 1-hr 4:54 p.m. 48 57

ST-4 Rio Salado Habitat Restoration Area 9/10/15 30-min 8:25 a.m. 92 48

ST-5 Central Ave and Cody Dr 9/9/15 1-hr 8:16 a.m. 27 54 ST-6 5425 S Central Ave 9/11/15 1-hr 7:03 a.m. 25 50 ST-7 Cigna Medical Group 9/10/15 1-hr 4:58 p.m. 25 58

V-1 Maricopa County Superior Courthouse: South Court Tower

9/8/15 10-min 7:27 p.m. 75 47


9/8/15 10-min 7:27 p.m. 100 47


9/8/15 10-min 7:27 p.m. 125 48


9/8/15 10-min 7:27 p.m. 150 47


9/8/15 10-min 7:27 p.m. 200 48


9/8/15 10-min 7:27 p.m. 250 47

V-2 1020 S Central Ave 9/9/15 15-min 7:34 p.m. 43 43 V-2 1020 S Central Ave 9/9/15 15-min 7:34 p.m. 63 45 V-2 1020 S Central Ave 9/9/15 15-min 7:34 p.m. 90 43 V-2 1020 S Central Ave 9/9/15 15-min 7:34 p.m. 115 42 V-2 1020 S Central Ave 9/9/15 15-min 7:34 p.m. 140 42 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 40 53 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 52 52 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 65 51 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 90 49 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 115 48 V-3 4216 S Central Ave 9/9/15 12-min 7:10 a.m. 155 52 V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 37 54 V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 49 54 V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 62 55 Noise and Vibration Technical Report 46 March 2016 Environmental Assessment South Central Light Rail Extension

TABLE 11: SUMMARY OF EXISTING VIBRATION MEASUREMENTS

Site Location Date Dur.a Start Time, hh:mm

Dist. from Near Lane

of Adjacent Street, ftb

Vibration at

Sensor, VdB

V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 87 54 V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 112 52 V-4 South Mountain Mortuary 9/10/15 10-min 7:10 a.m. 162 51 Source: ATS Consulting, 2015 data a Duration of measurement. b The distance of the microphone from the centerline of nearest lane of S. Central Ave and 1st Ave.


5.0 POTENTIAL OPERATIONAL NOISE AND VIBRATION

IMPACTS AND MITIGATION

5.1 LIGHT RAIL-RELATED NOISE

5.1.1 Operational Noise

The noise-sensitive land uses for FTA Categories 2 and 3 along the South Central Light Rail Extension Project have been grouped into clusters (note there are no Category 1 land uses). The clusters group similar land uses that are about the same distance from the tracks and are small enough that train speeds and other operational parameters are the same for all receivers in the cluster. The locations of the clusters and buildings included in each cluster are shown in Appendix F. The noise predictions are based on the sensitive receiver within each cluster that is closest to the South Central Light Rail Extension Project. Table 12 presents the predicted noise levels from train operations for Category 2 land use clusters, and Table 13 presents the predictions for Category 3 land use clusters. Category 2 land uses include residences and hotels. Category 3 land uses include schools, places of worship, medical facilities, courthouses and mortuaries. The columns in the tables provide the following information:

• ID: Identification for sensitive receiver cluster. The location of each sensitive receiver cluster is presented in the maps in Appendix F.

• Desc.: Describes the type of land use or name of the receiver.

• Near Track Dist.: Distance in feet from the near track centerline to the closest part of the noise-sensitive building or group of buildings.

• Speed: Maximum expected train speed on the track closest to the sensitive receiver. The speeds were based on the maximum projected speed for each section of the alignment. The actual train speeds would often be lower near train stations and signal stops.

• Exist. Noise Site: Indicates which noise measurement site was used to represent the existing noise.

• Existing: Estimated existing noise level (Ldn for Category 2, Leq for Category 3) at each sensitive receiver cluster based on the existing noise measurement results.

• Project: Predicted future Ldn or Leq or from train noise, including special trackwork and TPSS units. The noise predictions include bell noise from the trains at stops and stoplights and crossing gate bell noise. For each noise source, receivers out to a distance of 350 feet were evaluated; if there was an obstruction in the sound path from the noise source to the receiver (for example, a row of homes), the screening distance for bell noise was 175 feet. Note that wheel squeal was not included in any of the predictions; track curvature affects only nonrevenue operations, and it is assumed that proper friction modification or lubrication would be applied such that wheel squeal is not an issue.


• Impact Threshold: The FTA impact thresholds for moderate and severe impact are

based on the existing noise levels.

• Number of Impacts: The number of dwelling units within each cluster of sensitive receivers where the predicted levels of light rail noise meet or exceed the Moderate (Mod.) and Severe impact thresholds. Note that the number of units are those estimated to be facing, or exposed to, the noise from train operations.

As indicated in Section 1.0, LRVs have the potential to generate wheel squeal on the sharper curves used for infrequent, nonrevenue train movement. This noise element is not included in the noise impact analysis since all existing vehicles are equipped and all new vehicles would be equipped with friction control devices that would be used near sensitive receivers. Note that no revenue service train movements exist through low-radius curves. Following is a summary of the noise impact assessment of the proposed Build Alternative (the causes of impacts and recommended mitigation are described for each receiver in Section 5.3):

• Several moderate impacts and one severe impact are predicted from light rail operations at Category 2 land uses (residential or other sensitive receivers with both daytime and nighttime use, for example, residences, hotels, motels) as shown in Table 12. The moderate impacts occur at 11 sensitive receiver clusters that consist of 52 single-family residences. The moderate impacts are all less than 1 dB, with the exception of one receiver (receiver cluster SB-42, two homes on the southbound side just north of the Western Canal), which is 3 dB. Each of these moderate impacts is either near tracks with special trackwork or near a train station where train bells are sounded (or both), the two causes of the impacts. The severe impact occurs at a cluster of two single-family homes near tracks with special trackwork and near a TPSS unit (receiver cluster NB-13, northbound side near the intersection of Central Avenue and Raymond Street).

• No noise impacts are predicted from light rail operations at Category 3 land uses (institutional with primarily daytime use), as shown in Table 13.


TABLE 12: SUMMARY OF NOISE IMPACT ASSESSMENT FOR CATEGORY 2

IDa Desc.b Near Track

Dist. (ft) Sensitive Receiver

Location Speed (mph)

Exist. Noise Site

Ldnc (dBA) # of Impactsd

Existing Project Impact

Threshold Mod. Severe Mod. Severe

NB-01 HT 17 Hotel Palomar Phoenix 25 LT-1 70 61LX 65 70 — —

NB-02 MF 21 Barrister Place (potential multiuse redevelopment with residential component)

25 LT-1 70 63LX 65 70 — —

NB-03 HT 43 Luhrs (Tower) City Center Marriott (under construction) 25 LT-1 67 56LX 62 67 — —

NB-04 SF 198 700–722 S 1st St 30 LT-2 60 56X, TB 58 63 — —

NB-05 SF 148 734–800 S 1st St and 12 E Hadley St 30 LT-2 59 50X 57 63 — —

NB-06 SF 208 900–922 S 1st St 30 LT-2 60 51 58 63 — — NB-07 SF 54 1001–1009 S Central Ave 30 LT-2 70 60TB 64 69 — — NB-08 SF 210 1000–1022 S 1st St 30 LT-2 60 54TB 58 63 — — NB-09 SF 181 1706–1712 S 1st St 35 ST-3 65 53 61 66 — — NB-10 SF 340 1701–1725 S 1st St 35 ST-3 65 48 61 66 — — NB-11 SF 113 11–13 E Elwood St 35 LT-3 64 59X, TB 60 65 — — NB-12 SF 228 15–19 E Elwood St 35 LT-3 58 54X, TB 57 62 — — NB-13 SF 122 7–13 E Raymond St 35 LT-3 65 66X, TPSS 61 66 — 2

NB-14 SF 239 17–25 E Raymond St and 32 E Raymond St 35 LT-3 57 50X, TPSS 56 62 — —

NB-15 SF 240 15 E Jones Ave and 20–22 E Southgate Ave 35 LT-3 58 53TB 57 62 — —

NB-16 SF 180 14 E Southgate Ave 35 LT-3 64 56 60 66 — — NB-17 SF 176 17–27 E Southgate Ave 35 LT-3 64 56 60 66 — — NB-18 SF 212 18–22 E Riverside St 35 LT-3 63 55 60 65 — — NB-19 SF 263 23–29 E Riverside St 35 LT-3 62 59TB 59 64 6 — NB-20 SF 341 16 E Cody Dr 35 LT-3 58 50X 57 63 — — Noise and Vibration Technical Report 50 March 2016 Environmental Assessment South Central Light Rail Extension





Exist. Noise Site




NB-21 SF 305 25 E Roeser Rd 35 LT-4 60 50 58 64 — —

NB-22 SF 137 5403 S Central Ave, 2nd+ rows 35 LT-4 64 59TB 60 66 — —

NB-23 SF 108 5615 S Central Ave, 1st row 35 LT-4 69 63X, TB,

TPSS 63 69 3 —

NB-24 SF 214 5615 S Central Ave, 2nd row 35 LT-4 62 54X, TPSS 59 64 — — NB-25 SF 151 40 E Hidalgo Ave 35 LT-4 62 51 59 64 — — NB-26 SF 227 22–99 E Lynne Lane 35 LT-4 61 52 59 64 — — NB-27 SF 248 6210–6232 S 1st St 35 LT-4 62 51 59 64 — —

NB-28 SF 238 6234–6240 S 1st St and 20–22 E Alta Vista Rd 35 LT-4 61 54TB 59 64 — —

NB-29 SF 257 19 E St. Catherine Ave 35 LT-4 64 54 60 66 — —

NB-30 SF 175 14–26 E St. Anne Ave and 25 E St. Catherine Ave 35 LT-4 61 51 58 64 — —

NB-31 SF 191 15 E St. Anne Ave 35 LT-4 65 55 61 66 — —

NB-32 SF 172 19–25 E St. Anne Ave and 16–26 E St. Charles Ave 35 LT-4 63 53 59 65 — —

NB-33 SF 145 6645 S Central Ave 35 LT-4 67 58TB 62 67 — — NB-34 SF 239 21–25 E St. Charles Ave 35 LT-4 59 53TB 57 63 — — NB-35 SF 174 8–29 E Greenway Rd 35 LT-4 63 53 59 65 — —

NB-36 SF 96 7001 S Central Ave and 14 E Carter Rd 35 LT-4 69 59TPSS 63 69 — —

NB-37 SF 301 28–31 E Carter Rd 35 LT-4 60 50 58 64 — —

NB-38 MF 350 Westview Apartments on Sunland 35 LT-1 58 49TPSS 57 62 — —






Exist. Noise Site




NB-39 MF 36 Salvation Army Adult Rehab Center – residential 35 LT-2 67 62X, TPSS 63 68 — —

SB-01 SF 110 704–710 S 1st Ave 30 LT-2 64 59TB 60 66 — — SB-02 SF 221 113–115 W Grant St 30 LT-2 62 56TB 59 64 — —

SB-03 SF 99 801–821 S 1st Ave and 16 W Hadley St 30 LT-2 65 56LX, TPSS 61 66 — —

SB-04 SF 71 1010 S Central Ave 30 LT-2 68 59TB 63 68 — —

SB-05 MF 231 1001–1021 S 1st Ave and 21 W Tonto St 30 LT-2 58 53TB 57 62 — —

SB-06 SF 246 1105–1115 S 1st Ave 35 LT-2 59 54TB 57 63 — — SB-07 SF 303 1217–1221 S 1st Ave 35 LT-2 58 57TB 57 62 2 —

SB-08 SF 215 1301–1321 S 1st Ave and 2–98 W Papago St 35 LT-3 63 59TB 59 65 10 —

SB-09 SF 155 16–18 W Fulton St 35 LT-3 60 53X 58 64 — — SB-10 SF 265 22–30 W Fulton St 35 LT-3 56 49X 56 62 — — SB-11 SF 65 3716 S Central Ave 35 LT-3 70 63X, TPSS 65 70 — —

SB-12 SF 301 25 W Fulton St and various on W West Rd 35 LT-3 57 48X 56 62 — —

SB-13 MF 257 20–28 W Illini St 35 LT-3 60 51 58 63 — —

SB-14 SF 280 11–29 W Illini St and 32 W Jones Ave 35 LT-3 59 51 57 63 — —

SB-15 SF 175 15, 20 W Jones Ave 35 LT-3 60 55TB 58 63 — —

SB-16 SF 270 35 W Jones Ave and 20–34 W Southgate Ave 35 LT-3 57 52TB 56 62 — —

SB-17 SF 261 19–35 W Southgate Ave and 20–32 W Riverside St 35 LT-3 58 49 57 62 — —






Exist. Noise Site




SB-18 SF 366 31 W Riverside St and 30–34 W Pueblo Ave 35 LT-3 58 49 57 62 — —

SB-19 SF 107 4216 S Central Ave 35 LT-3 67 62TB 62 68 2 —

SB-20 SF 198 11 W Corona Ave and 20 W Marguerite Ave 35 LT-3 64 55 60 66 — —

SB-21 SF 300 21–29 W Corona Ave and 30–106 W Marguerite Ave 35 LT-3 55 47 55 61 — —

SB-22 SF 343 30–32 W Tamarisk Ave 35 LT-3 56 52TB 56 62 — —

SB-23 SF 68 S Central Ave and W Cody Dr, 1st and 2nd rows 35 LT-3 72 65X, TB 65 71 16 —

SB-24 SF 265 S Central Ave and W Cody Dr, 3rd and 4th rows 35 LT-4 57 50X 56 62 — —

SB-25 SF 382 1008 W Roeser Rd 35 LT-4 57 47 56 62 — —

SB-26 SF 187 17–23 W Roeser Rd, 100 W Grove St, 5223 S 1st Ave 35 LT-4 62 59TB 59 65 4 —

SB-27 SF 312 101–107 W Roeser Rd, 102–108 W Grove St 35 LT-4 57 57TB 56 62 4 —

SB-28 SF 182 5227-5249 S 1st Ave 35 LT-4 66 60TB 61 67 — —

SB-29 SF 354 101 W Grove St, 102 W Chambers St 35 LT-4 56 56TB 56 62 2 —

SB-30 SF 199 5403–5421 S 1st Ave 35 LT-4 65 55 61 67 — —

SB-31 SF 348 101 W Chambers St, 102 W Bowker St 35 LT-4 56 46 56 62 — —

SB-32 SF 200 5423 S 1st Ave, 101 W Bowker St, 20–24 W Sunland Ave

35 LT-4 61 55X, TB 58 64 — —






Exist. Noise Site




SB-33 SF 329 103-107 W Bowker St, 104-106 W Sunland Ave 35 LT-4 57 52TB 56 62 — —

SB-34 SF 354 105 W Sunland Ave 35 LT-4 60 50 58 63 — — SB-35 SF 371 6202–6222 S 1st Ave 35 LT-4 59 49 57 63 — — SB-36 SF 371 6224–6244 S 1st Ave 35 LT-4 59 49 57 63 — —

SB-37 MF 236 17–107 W Alta Vista Rd, 16–108 W St. Catherine Ave 35 LT-4 62 54TB 59 64 — —

SB-38 SF 199 27–35 W St. Charles Ave 35 LT-4 62 55TB 59 65 — —

SB-39 SF 228 6810 S Central Ave, 90 W Maldonado Pl 35 LT-4 62 54TB 59 64 — —

SB-40 MF 246 22–104 W Carson Rd, 17–29 W Carson Rd 35 LT-4 60 49 58 63 — —

SB-41 SF 249 26–34 W Fremont Rd, 25 W Fremont Rd 35 LT-4 62 54TB 59 64 — —

SB-42 SF 64 7252 S Central Ave, 1st row, and 7246 S Central Ave 35 LT-4 70 67X, TB 64 69 2 —

SB-43 SF 316 7252 S Central Ave, 2nd row 35 LT-1 58 57TB 57 62 1 — SB-44 MF 338 825 N 2nd Ave 25 LT-1 55 44LX 55 61 — — SB-45 HT 315 631 N 1st Ave 25 LT-1 70 50LX 64 70 — — a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SF = single-family residence, MF = multifamily residence, HT=hotel c Rounded to nearest whole number in accordance with FTA guidance. X: Includes special trackwork (standard crossover) noise. LX: Includes special trackwork from crossover that is already known to be low-impact (moveable point/spring frog). CB: Includes crossing gate bell noise. TB: Includes train bell noise at stoplights or train stations. TPSS: Includes TPSS unit noise. d Number of Impacts. This is a count of the number of properties/units represented for each potentially impacted sensitive receiver cluster.



IDa Desc.b Near Track Dist. (ft)


Speed (mph)

Exist. Noise Site

Leqc (dBA) # of Impactsd



NB-A SC 52 Arizona Summit Law School 25 ST-1 72 55LX 70 76 — —

NB-B Court 33 Maricopa County Justice Courts 25 LT-1 67 53LX 68 73 — —

NB-C SC 36 Salvation Army Adult Rehab Center 35 LT-2 72 68X, TB,

TPSS 70 76 — —

NB-D Habitat 50 Rio Salado Habitat Restoration Area 35 ST-4 65 58TB 66 71 — —

NB-E Habitat 50 Rio Salado Habitat Restoration Area – Audubon Center

30 ST-4 65 65CB 66 71 — —

NB-E1 SC 290 Rio Salado Audubon Center buildings – includes classroom 30 ST-4A 57 55CB, TB 61 67 — —

NB-F CH 49 Revealed Word Church 35 LT-3 70 61X, TPSS 69 75 — —

NB-G CH 91 Espiritu School Chapel and Offices 35 ST-5 64 56TB 65 71 — —

NB-H SC 304 Espiritu Schools 35 ST-5 56 49TB 61 66 — — NB-I CH 148 Central DI Ministries 35 ST-6 66 55X, TB 66 72 — — NB-J HP 95 Southside Animal Hospital 35 ST-8 67 59TB 67 73 — —

NB-K SC 110 Saint Catherine of Siena Catholic School 35 ST-8 66 55TB 67 72 — —

NB-L CH 68 South Mountain Mortuary 35 LT-4 71 57TB, TPSS 70 75 — — NB-M CH 357 Christian Science First Church 25 ST-1 61 45LX 63 69 — —

SB-A Court 95 Superior Court of Arizona in Maricopa County 25 LT-1 63 49LX 64 70 — —

SB-B Court/ LB 51 Maricopa East Court

Building/Law Library 25 LT-1 63 53LX,TB 65 70 — —





Speed (mph)

Exist. Noise Site

Leqc (dBA) # of Impactsd



SB-C Court 130 Maricopa County Superior Courthouse 25 LT-1 62 50TB 64 70 — —

SB-D SC 285 Friendly House – Adult Education and Workforce Development

30 ST-2 60 47LX 63 68 — —

SB-E CH 210 Saint Anthony Catholic Church 30 ST-2 63 50 64 70 — — SB-F CH 207 Iglesia Apostolica Cristiana 35 LT-3 63 53X 64 70 — — SB-G CH 49 Preston Funeral Home 35 LT-3 71 58X, TPSS 70 75 — — SB-H SC 134 Preschool 35 ST-5 63 54TB 65 70 — — SB-I SC 56 Phoenix Collegiate Academy 35 ST-6 73 64X, TB 70 76 — — SB-J LB 381 Ocotillo Library 35 ST-6 56 43 61 67 — —

SB-K CH 106 Saint Catherine of Siena Roman Catholic Church 35 ST-8 67 54TB 67 72 — —

SB-L CH 80 Southern Baptist Temple 35 ST-8 68 55 68 73 — —

SB-M SC 110 St. John Bosco Chapel/ St. Catherine of Siena Catholic Preschool

35 ST-8 67 54 67 72 — —

SB-N MD 142 Cigna Medical Group 35 ST-7 64 57X, TB,

TPSS 65 71 — —

SB-O SC 180 Phoenix College Downtown 25 LT-1 67 48LX 67 73 — — a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SC = school, CH = church, MD = medical, Court = courthouse, LB = library, Habitat = habitat restoration area c Maximum 1-hour Leq during daytime when facility is in use. Rounded to nearest whole number in accordance with FTA guidance. X: Includes special trackwork (standard crossover) noise. LX: Includes special trackwork from crossover that is already known to be low-impact (moveable point/spring frog). CB: Includes crossing gate bell noise. TB: Includes train bell noise at stoplights or train stations. TPSS: Includes TPSS unit noise. d Number of Impacts. This is a count of the number of properties/units represented for each potentially impacted sensitive receiver cluster.


5.1.2 Ancillary Equipment

TPSS units are the only ancillary equipment associated with the proposed project with the potential to cause noise impacts. Six locations are being evaluated, and five will be selected. The locations of the TPSS units are shown in the receiver drawings (as pink polygons) in Appendix F. All of the selected sites are adjacent to at least one sensitive receiver being evaluated. It is common to include noise limits in the purchase specifications for TPSS units to minimize the potential for noise impacts from TPSS noise. The specifications generally include maximum noise limits for potential noise generators, such as the transformer hum and any cooling systems. The cooling fans are the major noise source on many modern TPSS units, and the transformer hum is usually inaudible except when very close to the TPSS unit. In addition to evaluating the TPSS units as part of the project noise, they are also examined separately for nighttime noise at residential receivers. The typically adopted design goal for noise from TPSS units is at least 5 decibels lower than the nighttime ambient level. The first step in controlling TPSS noise is to include a noise limit in the purchase specifications for TPSS units. The recommended limit is that the maximum noise level not exceed 50 dBA at a distance of 50 feet from any part of a TPSS unit. In addition, the cooling fans should be oriented away from the nearest receiver to minimize the noise at the receiver. Table 14 shows the predicted levels of TPSS noise at nearby residences, along with the measured nighttime Leq for the site. A noise impact is indicated when the predicted TPSS nighttime Leq noise level exceeds the existing nighttime Leq minus 5 decibels. This approach for assessing TPSS noise impact is more stringent than the FTA impact criteria and ensures no impacts are overlooked. As seen in Table 14, the only impact is seen for the TPSS unit located at the southeast corner of Central Avenue and Raymond Street. Here, receiver NB-13 (two single-family residences: 7 E. Raymond Street and 13 E. Raymond Street) is very close to the TPSS unit, resulting in the impact. This is the same receiver showing a severe impact for project noise in Table 12, with the TPSS unit contributing to the impact.


TABLE 14: PREDICTED NIGHTTIME TPSS NOISE

TPSS Unit Site

TPSS Unit Location

Residence Existing Nighttime Leq (dBA)a

Predicted TPSS Leq

(dBA)b

Impact Threshold

(dBA) Impact

ID Distance to Unit (ft)

1 Northwest corner Central Ave/ Hadley St

SB-4 130 57 42 52 No

2 Northwest corner Central Ave/ Cocopah St

NB-39 100 59 44 54 No

3 Southeast corner Central Ave/ Raymond St

NB-13 21 57 58 52 Yes NB-14 106 49 43 44 No SB-12 158 63 40 58 No

4 Northeast corner Central Ave/ Sunland Ave

NB-23 204 60 38 55 No NB-24 260 54 36 49 No NB-38 102 50 44 45 No

5 Northeast corner Central Ave/ Carter Rd

NB-36 84 61 45 56 No

6 Southeast corner Central Ave/Jesse Owens Pkwy

SB-43 144 61 41 56 No

a Nighttime Leq measured between the hours of 10 p.m. and 7 a.m. b Predicted TPSS noise is based on a maximum noise level of 50 dBA at 50 feet from any part of the TPSS.

5.1.3 Traffic Noise Attributable to Roadway and Traffic/Bus Volume Changes

The South Central Light Rail Extension Project involves some physical roadway changes and bus headway changes, as described in Section 1.0. Traffic volume differences are also predicted for the Build and No-Build Alternatives. The following modifications have the potential to change the noise environment and were, therefore, evaluated using FHWA’s TNM. The evaluation concluded that traffic noise is not an issue for this project, as discussed below:

• On Central Avenue, there will be road widening related to flaring, combined with Build/No-Build traffic differences, elimination of the RAPID bus and a decrease in bus service headways (frequencies) for Route 0. The flaring occurs for different degrees at the following intersections: Buckeye Road/Central Avenue, Broadway Road/Central Avenue, Southern Avenue/Central Avenue and Baseline Road/Central Avenue. The intersections would be flared to accommodate the light rail and necessary turn and through lanes. Predictions were made for the No-Build and Build Alternatives. The analysis examined the effect resulting from the largest lane shift (from flaring), combined with the change in bus service along Central Avenue and decrease in road traffic comparing the Build and No-Build Alternatives. The analysis showed that there would actually be a decrease in sound level adjacent to Central Avenue (1 to 2 dB), with the exception of very short distances to the road (25 feet), where there was a slight increase (less than 1 dB). The lane shift increases the


noise, particularly close to the road; the decrease in bus service frequencies decreases the noise and the decrease in traffic decreases the noise. Therefore, the combined effect is minimal and negligible very close to the road and slightly decreases the noise farther from the road. Given the minimal combined effect, these changes are not included in project noise predictions.

• On Central Avenue, two roundabouts would be introduced, as described in Section 1.0. Only the roundabout adjacent to the Rio Salado Habitat Restoration Area and Audubon Center south of the Salt River is located near sensitive receivers (sensitive receivers NB-E and NB-E1). The roundabout moves some of the traffic closer and some farther from the receivers. As with the first analysis, the traffic volumes (including buses) decrease because of the project. The result of the analysis showed a net decrease in sound level. As a result, these changes are not included in the project noise predictions.

• On Baseline Road, bus volumes would change as a result of the project. The RAPID bus would be eliminated and Route 77 volumes would increase because of the addition of the Route 77A bus overlay service, which would shuttle riders between the Baseline Road/Central Avenue light rail station and two existing park-and-ride lots along Baseline Road both east and west of Central Avenue. To simplify the analysis, for this scenario, predictions were made for just the No-Build Alternative with and without the bus changes, to isolate the effect of the bus changes. The analysis showed that there would be no change in sound level attributable to the bus change, since the elimination of one line and increase in volume of another line results in the same maximum number of buses during peak hour. Therefore, the change in buses along Baseline Road warrants no further consideration.

• At the intersection of 7th Avenue and Southern Avenue, right-turning traffic would be shifted slightly closer (estimated 2-3 feet) to sensitive receivers due to the addition of right turn lanes, resulting in a less than 1 dB noise increase; through traffic would be shifted slightly farther from sensitive receivers, resulting in a less than 1 dB noise decrease. The combined effect of the intersection changes is negligible; as a result, these changes are not included in the project noise predictions.

The other modifications would not result in a potential noise increase or are not near any sensitive receivers, so evaluations are not warranted.

5.1.4 Other Noise

5.1.4.1 Park-and-Ride Facilities

The park-and-ride lots to be used for the project consist of one proposed at Broadway Road and Central Avenue, one proposed near Fremont Road and Central Avenue (near the proposed Baseline Road station) and two existing facilities along Baseline Road. An existing transit center is at Broadway Road and Central Avenue, and an approximate 80-space adjacent lot would be added as part of the project. The closest sensitive receiver is at a distance of 115 feet. At that distance, the noise from an 80-space parking lot would result in a peak hour Leq of 42 dBA. In the area, the existing noise is approximately 69 dBA Leq peak and Ldn. Since the park-and-ride lot noise is so far Noise and Vibration Technical Report 59 March 2016 Environmental Assessment South Central Light Rail Extension

below the existing noise, the changes in the parking lot would not result in an increase in noise at the surrounding receivers. Therefore, no further consideration is warranted. On the west side of Central Avenue, between Fremont Road and the Western Canal (near the proposed Baseline Road station), an approximate 365-space lot would be added as part of the project. This T-shaped lot connects to both Fremont Road and Central Avenue. Several sensitive receivers surround the lot, ranging from distances of 25 to 65 feet from various edges of the lot. The existing noise for the surrounding receivers ranges from 52 to 64 dBA Leq peak. The predicted lot noise levels, based on the number of spaces and entering/exiting vehicles affecting each receiver, are all below the existing noise levels. Although below the existing levels, some were within 10 dB and, therefore, warranted an examination that includes other project noise. When the lot noise is combined with the other project noise (train operations, TPSS, etc.), no potential noise impacts are predicted for any of the surrounding receivers other than where a moderate impact was already predicted at SB-43. For that receiver, the impact exceedance does not increase because of the park-and-ride lot. In summary, the analysis shows that the lot near Central Avenue and Fremont Road does not contribute to potential project noise impacts for any sensitive receiver, based on FTA impact limits. For the two existing lots on Baseline Road, no substantial change to current use is anticipated as a result of the project since passengers now parking there to ride the RAPID line to Downtown Phoenix would continue to park there after the RAPID line is eliminated and would instead use the local bus route to go to the end-of-line Baseline Road/Central Avenue station to ride the light rail. Therefore, these lots require no further consideration of noise impact.

5.1.4.2 Operations and Maintenance Center Expansion

Although the proposed project includes planned improvements to facilities at the existing OMC, east of Phoenix Sky Harbor International Airport and southwest of the intersection of Grand Canal and Loop 202, no receivers are found in the vicinity that are sensitive to noise and vibration impacts. As a result, no noise or vibration impacts are predicted from the expansion of the OMC.

5.2 LIGHT RAIL OPERATIONAL VIBRATION

As discussed in Section 2.3, the FTA Guidance Manual provides two criteria for assessing vibration impacts. The first criterion is based on the overall vibration velocity level and is intended for use with a General Assessment. The second FTA criterion is based on the 1/3 octave band spectrum of the predicted vibration. FTA indicates that the second criterion is intended for use with a Detailed Assessment when vibration propagation testing has been performed and the predictions include the vibration spectrum. Note that no impact criteria exist for outdoor spaces. As discussed in Section 3.4.2, vibration propagation tests were performed at four locations in the project corridor and were used as the basis for the vibration prediction model. Therefore, it is appropriate to apply the Detailed Assessment criteria to more accurately identify potential vibration impacts. The key thresholds applicable to the South Central Light Rail Extension are a maximum vibration level of 72 VdB for Category 2 (residential) land uses and 78 VdB for Noise and Vibration Technical Report 60 March 2016 Environmental Assessment South Central Light Rail Extension

Category 3 (institutional) land uses. The thresholds apply to 1/3 octave frequencies on the range of 8 to 80 Hz. This means that for residential land uses, an impact would occur if any 1/3 octave band level between 8 and 80 Hz is predicted to exceed 72 VdB. (Note that no vibration Category 1 properties exist along the corridor, which would include vibration-sensitive research and manufacturing, hospitals with vibration-sensitive equipment and university research operations.) Limits are also set by FTA for maximum groundborne noise: 35 dBA for Category 2 and 40 dBA for Category 3. Groundborne noise radiates off the structure and is caused directly by groundborne vibration. However, in most cases, the airborne noise from at-grade LRV traffic dominates the noise source. In this case the vibration propagation is very efficient at 80 to 100 Hz, and the FDL is quite high at 80 Hz (Section 3.4.4). Therefore, the groundborne vibration predictions will be higher than typical. Additionally, several receivers do not have windows, or a significant coverage of windows, facing the alignment. At these receivers, the airborne noise would not be a significant factor and groundborne noise must be considered closely. Specific limits for groundborne noise, based on the predicted level of indoor airborne noise, have been defined for each receiver as part of the prediction model. The vibration predictions are presented in Tables 15 and 16 for Category 2 and Category 3 land uses, respectively. The data presented in the tables include:

• ID: Identification number. The location of each sensitive receiver cluster is presented in the maps in Appendix F.

• Desc.: Describes the type of land use or name of the receiver.

• Near Track Dist.: Distance in feet from the near track centerline to the facade of the closest vibration-sensitive building.

• Groundborne Vibration: The predicted level of light rail vibration in VdB. These predictions are a single value representing the maximum level in a single 1/3 octave band. This value is compared to the FTA Detailed Assessment criteria to determine impact.

• Groundborne Noise: Predicted groundborne noise in dBA based on overall vibration level.

• GBN Limit: Receiver-specific limit for groundborne noise, in dBA. This limit is based on the predicted indoor noise level of a single train passby. Groundborne noise impact is defined if the groundborne noise exceeds the airborne noise indoors.

• GBV Impact: Indicates “Y” for yes as to whether the predicted levels exceed the applicable Detailed Assessment criterion curve, based on maximum vibration levels compared to 72 VdB (Category 2) or 78 VdB (Category 3) limits.

• GBN Impact: Indicates “Y” for yes as to whether the predicted levels exceed the applicable limit set for each receiver. The limit for each receiver is given in column “GBN Limit.”

As shown in Table 15, vibration impact is predicted at several Category 2 (residential) sensitive receivers. Several receivers in the Downtown area are less than 50 feet from the alignment, including the Hotel Palomar, the Barrister Building and the future hotel


development on the Luhrs Tower property. Scattered vibration impacts to receivers throughout the alignment also occur outside the Downtown area at the following locations:

• NB-07 1001-1009 S. Central Avenue

• SB-11 3716 S. Central Avenue

• SB-23 homes in northwest quadrant of S Central Avenue and W Cody Drive

• SB-42 7252 S. Central Avenue (1st row homes) and 7246 S. Central Avenue. As shown in Table 16, several groundborne vibration and noise impacts are predicted at Category 3 (institutional) sensitive receivers. One is at a government courthouse building (Maricopa County Justice Courts) and another at a school (Arizona Summit Law School) in the Downtown area. A number of Category 3 receivers are located farther south throughout the alignment. Three of these have predicted groundborne noise and vibration impacts:

• NB-C Salvation Army Adult Rehabilitation Center (classrooms)

• NB-F Revealed World Church

• SB-I Phoenix Collegiate Academy.


TABLE 15: SUMMARY OF VIBRATION IMPACT ASSESSMENT FOR CATEGORY 2



Speed (mph)

Groundborne Vibrationc,d

(VdB)

Groundborne Noised (dBA)

GBN Criteriad

(dBA)

GBV Impact

GBN Impact

NB-01 HT 17 Hotel Palomar Phoenix 25 78 53 44 Y Y

NB-02 MF 21 Barrister Place (potential multiuse redevelopment with residential component)

25 77 53 43 Y Y

NB-03 HT 43 Luhrs City Center Marriott (under construction) 25 64 38 40 — —

NB-04 SF 198 700–722 S 1st St 30 61 30 42 — —

NB-05 SF 148 734–800 S 1st St and 12 E Hadley St 30 62 34 41 — —

NB-06 SF 208 900–922 S 1st St 30 60 30 41 — — NB-07 SF 54 1001–1009 S Central Ave 30 72e 47 50 Y — NB-08 SF 210 1000–1022 S 1st St 30 60 30 41 — — NB-09 SF 181 1706–1712 S 1st St 35 62 33 43 — — NB-10 SF 340 1701–1725 S 1st St 35 60 25 39 — — NB-11 SF 113 11–13 E Elwood St 35 67 40 45 — — NB-12 SF 228 15–19 E Elwood St 35 61 30 40 — — NB-13 SF 122 7–13 E Raymond St 35 70 42 48 — —

NB-14 SF 239 17–25 E Raymond St and 32 E Raymond St 35 61 30 39 — —

NB-15 SF 240 15 E Jones Ave and 20–22 E Southgate Ave 35 61 29 40 — —

NB-16 SF 180 14 E Southgate Ave 35 62 33 46 — — NB-17 SF 176 17–27 E Southgate Ave 35 62 33 47 — — NB-18 SF 212 18–22 E Riverside St 35 62 31 46 — — NB-19 SF 263 23–29 E Riverside St 35 61 28 45 — — NB-20 SF 341 16 E Cody Dr 35 60 25 41 — —





Speed (mph)


(VdB)


GBN Criteriad

(dBA)

GBV Impact

GBN Impact

NB-21 SF 305 25 E Roeser Rd 35 60 27 41 — — NB-22 SF 137 5403 S Central Ave, 2nd+ rows 35 64 36 45 — — NB-23 SF 108 5615 S Central Ave, 1st row 35 71 44 49 — — NB-24 SF 214 5615 S Central Ave, 2nd row 35 62 31 43 — — NB-25 SF 151 40 E Hidalgo Ave 35 63 35 42 — — NB-26 SF 227 22–99 E Lynne Lane 35 61 30 42 — — NB-27 SF 248 6210–6232 S 1st St 35 61 29 42 — —

NB-28 SF 238 6234–6240 S 1st St and 20–22 E Alta Vista Rd 35 61 30 42 — —

NB-29 SF 257 19 E St. Catherine Ave 35 61 29 45 — —

NB-30 SF 175 14–26 E St. Anne Ave and 25 E St. Catherine Ave 35 62 33 42 — —

NB-31 SF 191 15 E St. Anne Ave 35 62 32 46 — —

NB-32 SF 172 19–25 E St. Anne Ave and 16–26 E St. Charles Ave 35 62 33 44 — —

NB-33 SF 145 6645 S Central Ave 35 64 35 47 — — NB-34 SF 239 21–25 E St. Charles Ave 35 61 30 40 — — NB-35 SF 174 8–29 E Greenway Rd 35 62 33 44 — —

NB-36 SF 96 7001 S Central Ave and 14 E Carter Rd 35 67 41 49 — —

NB-37 SF 301 28–31 E Carter Rd 35 60 27 41 — — NB-38 MF 350 Westview Apartments 25 56 22 36 — —

NB-39 MF 68 Salvation Army Adult Rehab Center – Residential 25 69 43 48 — —

SB-01 MF 110 704–710 S 1st Ave 30 65 38 47 — — SB-02 SF 221 113–115 W Grant St 30 60 29 44 — —





Speed (mph)


(VdB)


GBN Criteriad

(dBA)

GBV Impact

GBN Impact

SB-03 SF 206 801–821 S 1st Ave and 16 W Hadley St 30 65 39 48 — —

SB-04 SF 84 1010 S Central Ave 30 69 43 49 — —

SB-05 SF 244 1001–1021 S 1st Ave and 21 W Tonto St 30 60 29 39 — —

SB-06 MF 270 1105–1115 S 1st Ave 35 61 29 42 — — SB-07 SF 329 1217–1221 S 1st Ave 35 60 27 39 — —

SB-08 SF 230 1301–1321 S 1st Ave and 2–98 W Papago St 35 62 31 46 — —

SB-09 SF 168 16–18 W Fulton St 35 63 35 42 — — SB-10 SF 278 22–30 W Fulton St 35 61 28 38 — — SB-11 SF 78 3716 S Central Ave 35 74 48 51 Y —

SB-12 SF 314 25 W Fulton St and various on W West Rd 35 60 27 39 — —

SB-13 SF 270 20–28 W Illini St 35 61 29 42 — —

SB-14 MF 293 11–29 W Illini St and 32 W Jones Ave 35 60 28 42 — —

SB-15 SF 188 15, 20 W Jones Ave 35 62 33 42 — —

SB-16 SF 283 35 W Jones Ave and 20–34 W Southgate Ave 35 61 28 40 — —

SB-17 SF 277 19–35 W Southgate Ave and 20–32 W Riverside St 35 61 28 40 — —

SB-18 SF 391 31 W Riverside St and 30–34 W Pueblo Ave 35 59 25 40 — —

SB-19 SF 132 4216 S Central Ave 35 66 39 49 — —

SB-20 SF 214 11 W Corona Ave and 20 W Marguerite Ave 35 62 32 46 — —





Speed (mph)


(VdB)


GBN Criteriad

(dBA)

GBV Impact

GBN Impact

SB-21 SF 316 21–29 W Corona Ave and 30–106 W Marguerite Ave 35 60 27 38 — —

SB-22 SF 356 30–32 W Tamarisk Ave 35 59 25 39 — —

SB-23 SF 87 S Central Ave and W Cody Dr, 1st and 2nd rows 35 75 49 50 Y —

SB-24 SF 278 S Central Ave and W Cody Dr, 3rd and 4th rows 35 61 28 40 — —

SB-25 SF 395 1008 W Roeser Rd 35 59 24 38 — —

SB-26 SF 211 17–23 W Roeser Rd, 100 W Grove St, 5223 S 1st Ave 35 62 32 43 — —

SB-27 SF 336 101–107 W Roeser Rd, 102–108 W Grove St 35 60 26 38 — —

SB-28 SF 206 5227–5249 S 1st Ave 35 62 33 46 — —

SB-29 SF 377 101 W Grove St, 102 W Chambers St 35 59 25 37 — —

SB-30 SF 213 5403–5421 S 1st Ave 35 62 32 46 — —

SB-31 SF 362 101 W Chambers St, 102 W Bowker St 35 59 25 37 — —

SB-32 SF 213 5423 S 1st Ave, 101 W Bowker St, 20–24 W Sunland Ave 35 62 32 41 — —

SB-33 SF 342 103–107 W Bowker St, 104–106 W Sunland Ave 35 60 26 37 — —

SB-34 SF 367 105 W Sunland Ave 35 59 25 40 — — SB-35 SF 386 6202–6222 S 1st Ave 35 59 24 40 — — SB-36 SF 384 6224–6244 S 1st Ave 35 59 24 40 — —

SB-37 SF 249 17–107 W Alta Vista Rd, 16–108 W St. Catherine Ave 35 61 30 42 — —





Speed (mph)


(VdB)


GBN Criteriad

(dBA)

GBV Impact

GBN Impact

SB-38 MF 212 27–35 W St. Charles Ave 35 62 32 43 — —

SB-39 SF 241 6810 S Central Ave, 90 W Maldonado Pl 35 61 30 42 — —

SB-40 SF 259 22–104 W Carson Rd, 17–29 W Carson Rd 35 61 29 40 — —

SB-41 MF 262 26–34 W Fremont Rd, 25 W Fremont Rd 35 61 29 42 — —

SB-42 SF 103 7252 S Central Ave, 1st row, and 7246 S Central Ave 35 76 50 51 Y —

SB-43 SF 355 7252 S Central Ave, 2nd row 35 60 26 39 — — SB-44 SF 467 825 N 2nd Ave 25 57 23 36 — — SB-45 MF 423 631 N 1st Ave 25 47 13 41 — — Note: Refer to Table F-1 in Appendix F for indications of special trackwork for each receiver; the special trackwork increases vibration levels. a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b Desc. = Type of land use, SF = single-family residence, MF = multifamily residence, HT = hotel. c Groundborne vibration is level in VdB of maximum 1/3 octave band, compared to 72 VdB. d Predictions and limits are shown to the nearest decibel. e These impacts represent fractional exceedances of less than 1 dB (still considered an impact).





Speed (mph)


(VdB) Groundborne Noised (dBA)

GBN Criteriad

(dBA)

GBV Impact

GBN Impact

NB-A SC 52 Arizona Summit Law School 25 66 40e 40 — Y NB-B Court 33 Maricopa County Justice Courts 25 67 41e 41 — Y

NB-C SC 36 Salvation Army Adult Rehab Center 35 78e 53 43 Y Y

NB-E1 SC 290 Rio Salado Audubon Center buildings – includes classroom 30 59 26 43 — —

NB-F CH 49 Revealed Word Church 35 78e 52e 52 Y Y NB-G CH 91 Espiritu School Chapel and Offices 35 67 41 49 — — NB-H SC 304 Espiritu Schools 35 60 27 41 — — NB-I CH 148 Central DI Ministries 35 63 35 47 — — NB-J HP 95 Southside Animal Hospital 35 67 41 49 — —

NB-K SC 110 Saint Catherine of Siena Catholic School 35 66 39 49 — —

NB-L CH 68 South Mountain Mortuary 35 71 45 51 — — NB-M CH 357 Christian Science First Church 25 56 22 41 — —

SB-A Court 95 Superior Court of Arizona in Maricopa County 25 54 28 40 — —

SB-B Court 51 Maricopa East Court Building/Law Library 25 61 36 40 — —

SB-C Court 130 Maricopa County Superior Courthouse 25 52 24 40 — —

SB-D SC 285 Friendly House – Adult Education and Workforce Development 30 59 26 43 — —

SB-E CH 210 Saint Anthony Catholic Church 30 60 30 44 — — SB-F CH 207 Iglesia Apostolica Cristiana 35 62 32 46 — — SB-G CH 49 Preston Funeral Home 35 75 49 52 — —





Speed (mph)


(VdB) Groundborne Noised (dBA)

GBN Criteriad

(dBA)

GBV Impact

GBN Impact

SB-H SC 134 Preschool 35 64 36 48 — — SB-I SC 56 Phoenix Collegiate Academy 35 82 57 52 Y Y SB-J LB 381 Ocotillo Library 35 59 24 43 — —

SB-K CH 106 Saint Catherine of Siena Roman Catholic Church 35 66 39 44 — —

SB-L CH 80 Southern Baptist Temple 35 69 43 50 — —

SB-M SC 110 St. John Bosco Chapel/ St. Catherine of Siena Catholic Preschool

35 66 39 49 — —

SB-N MD 142 Cigna Medical Group 35 67 39 47 — — SB-O SC 180 Phoenix College Downtown 25 59 30 44 — — Note: Refer to Table F-1 in Appendix F for indications of special trackwork for each receiver; the special trackwork increases vibration levels. a ID identifies sensitive receivers as shown in the maps in Appendix F; note that NB-D and NB-E are habitat restoration areas that are not assessed for vibration. NB = northbound side, SB = southbound side. b Desc. = Type of land use, SC = school, CH = church, MD = medical, Court = courthouse, LB = library. c Groundborne vibration is level in VdB of maximum 1/3 octave band, compared to 78 VdB. d Predictions and limits are shown to the nearest decibel. e These impacts represent fractional exceedances of less than 1 dB (still considered an impact).


5.3 OPERATIONAL NOISE MITIGATION

Table 17 summarizes noise limit exceedances and mitigation recommendations for each potentially impacted sensitive receiver. Impact exceedance is shown as exceedance of a moderate impact level (with severe impact noted). Also shown in the table is the cause of the impact. For the South Central Light Rail Extension Project, mitigation is recommended for the two exceedances greater than 1 dB, one moderate (SB-42, two homes) and one severe (NB-13, two homes). Mitigation is not recommended for exceedances less than 1 dB. The reasonableness of providing mitigation is a factor when considering mitigation. A less than 1 dB change in noise level with the project is negligible given that 3 dB is considered the threshold at which an average listener can detect change. This assumption is reasonable. In addition, in the case of train bells at stations causing the <1 dB exceedance, these bells are safety-related and already at a low level setting, so no mitigation is warranted. In the case of special trackwork causing the <1 dB exceedance, the exceedances are actually 0.0 and –0.2 dB (required rounding causes the level to meet the limit); so, in these cases, no mitigation is warranted. For all predictions and mitigation recommendations, it is assumed that the track and wheels would be maintained in a state of good repair (that is, rail corrugations and wheel flats would be minimized through maintenance procedures—rail grinding and wheel truing). For the potential moderate noise impacts near special trackwork (SB-42, two homes), low-impact frogs alone can be used to reduce the predicted noise levels to below the FTA impact threshold. Low-impact frogs can reduce noise levels by creating a smoother transition through the gap in the rails at the special trackwork. Examples of low-impact frogs include moveable point frogs, spring-rail frogs, monoblock frogs or flange-bearing frogs (refer to Appendix G for more information). Only one severe noise impact would occur at a residential receiver, at 7–13 E. Raymond Street (NB-13, two homes). By applying a low-impact frog, the impact is reduced to moderate with a 3.4-dB exceedance. To eliminate the impact, it is recommended to minimize noise from the nearby TPSS unit located 21 feet from the nearest residence at the southeast corner of Central Avenue and Raymond Street. (Note that minimizing the noise from the TPSS unit without applying the low-impact frog results in a moderate impact with an exceedance of 1.4 dB, so both sources of noise must be addressed to eliminate the impact.) To mitigate the noise from the TPSS unit, the TPSS unit should be strategically located within the site, with the major noise source, the cooling fans, being as far from the residences as possible. If the TPSS unit is located within the parcel as far as feasible and oriented with the cooling fans facing away from the sensitive receivers, the predicted noise level could be reduced to below the applicable threshold. The cooling fans on the TPSS unit should be facing east or south and be located more than 50 feet from the nearest residence to reduce the predicted noise levels to below the impact threshold (when combined with the low-impact frog). If there is not much flexibility on where to locate the unit within the parcel, a sound enclosure should be built around the TPSS unit to reduce noise levels at sensitive receivers; the sound enclosure would need to reduce noise by 3.4 dB, which is attainable with a proper design of the enclosure (appropriately considers the cooling fan height above ground). Since only five of the six TPSS locations being evaluated will be


chosen, it may be possible to eliminate this location as an option and thus remove the TPSS unit as a sound source for nearby receivers. The potential to eliminate any of the specific TPSS sites being considered will be determined as the design is refined and electrical load requirements can be calculated to assist in accurately determining TPSS locations for the proposed project.

TABLE 17: SUMMARY OF RECOMMENDED NOISE MITIGATION


Impact Exceedance Recommended Mitigation

(dB)c Cause

NB-13 SF 7–13 E Raymond St 5d Special trackwork, TPSS unit

Use low-impact frog for special trackwork at Raymond St; strategic placement/orientation of TPSS unit

NB-19 SF 23–29 E Riverside St <1 Train bells at

station Mitigation not recommended for exceedances of <1 dB

NB-23 SF 5615 S Central Ave, 1st row homes <1 Special

trackwork Mitigation not recommended for exceedances of <1 dB

SB-07 SF 1217–1221 S 1st Ave <1 Train bells at


SB-08 SF 1301–1321 S 1st Ave and 2–98 W Papago St

<1 Train bells at station

Mitigation not recommended for exceedances of <1 dB

SB-19 SF 4216 S Central Ave <1 Train bells at station


SB-23 SF S Central Ave and W Cody Dr., 1st and 2nd row homes

<1 Special trackwork


SB-26 SF 17–23 W Roeser Rd, 100 W Grove St, 5223 S 1st Ave



SB-27 SF 101–107 W Roeser Rd, 102–108 W Grove St



SB-29 SF 101 W Grove St, 102 W Chambers St <1 Train bells at


SB-42 SF 7252 S Central Ave, 1st row, and 7246 S Central Ave

3

Special trackwork, train bells at station

Use low-impact frog for special trackwork in the vicinity of Western Canal

SB-43 SF 7252 S Central Ave, 2nd row <1 Train bells at


a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SF = single-family c Moderate limit exceedance d This exceedance qualifies as a severe impact.

With implementation of the recommended mitigation measures, all noise levels would be reduced to less than 1 dBA of the applicable criteria levels or below. No significant adverse noise impacts are anticipated as a result of the proposed project. Noise and Vibration Technical Report 71 March 2016 Environmental Assessment South Central Light Rail Extension

5.4 OPERATIONAL VIBRATION MITIGATION

A variety of options exist for mitigating groundborne vibration and noise. The specific measure chosen may depend on the severity of impact and the proximity to certain track design features. Impacts attributable to groundborne vibration and noise are predicted at several receivers. Table 18 shows the impacts to Category 2 and Category 3 receivers and recommended mitigation. Impacts are predicted at two multifamily residential receivers Downtown, including the Palomar Hotel and Barrister Place. Groundborne noise and vibration impacts are predicted because of the proximity of the track (approximately 20 feet) and the presence of special trackwork. The Barrister Place building is currently vacant, but is planned for a multiuse redevelopment that will include a residential component. If it is not possible to relocate either the track or the special trackwork farther away from the Palomar Hotel or Barrister Place, then the recommended mitigation for the Palomar Hotel and Barrister Place is installation of isolated slab track. The design consists of a concrete slab supported by a continuous elastomeric support mat. This design is capable of attenuation greater than 10 dB at frequencies 25 Hz and higher. A less than 1 VdB exceedance of the vibration criteria threshold is anticipated for three single-family homes at cluster NB-07 on Central Avenue. A less than 1 dB exceedance of the groundborne noise criteria is also expected at the Arizona Summit Law School (NB-A) and the Maricopa County Justice Courts (NB-B). At these locations, a rail boot, a resilient material between the rail and the receiver, is the recommended mitigation measure. The most common design for embedded track on modern light rail systems is to use a rubber boot around the rail with the rail and boot embedded in concrete. The standard-booted embedded track system is relatively stiff and does not provide much isolation. However, several suppliers have developed embedded track systems that incorporate much softer rubber elements. Where relatively limited vibration attenuation is required, one of these systems will provide sufficient vibration attenuation. The proposed project is expected to exceed the vibration impact levels at the Salvation Army Adult Rehabilitation Center (NB-C) by less than 1 VdB and the groundborne noise threshold levels by approximately 10 dB. The recommended mitigation is to install a rail boot and a low-impact frog (described more in the next paragraph). For all other sensitive uses presented in Table 18, installation of low-impact frogs at the nearby special trackwork, such as loops and crossovers, is the recommended measure to mitigate groundborne noise and/or vibration impacts at these locations. The gaps in the rail associated with standard frogs can cause vibration levels to increase by up to 10 decibels. Low-impact frogs can reduce vibration levels by creating a smoother transition through the gap in the rails at the special trackwork. Examples of low-impact frogs include monoblock frogs, flange-bearing frogs, moveable point frogs or spring rail frogs. Where possible, special trackwork may also be relocated farther away from the receiver. More information on low-impact frogs is included in Appendix G. With implementation of the recommended mitigation where needed, the proposed project would not result in exceedances of the applicable groundborne noise or vibration


criteria thresholds. Therefore, the project would have no significant adverse groundborne noise or vibration impacts.


TABLE 18: SUMMARY OF VIBRATION MITIGATION FOR SENSITIVE RECEIVERS

IDa D

escr

iptio

nb Sensitive Receiver Location

GBV (VdB)

GBN (dBA)

# of

Uni

ts

Recom-mended

Mitigationd

Mitigation, Feet



Lim

it

Pred

ict

Lim

it

Pred

ict

NB-01 HT Hotel Palomar Phoenix 72 78 44 53 190 Isolated

slab track 65

480 NB-02 MF

Barrister Place (potential multiuse re-development with residential component)

72 77 43 53 35 Isolated slab track 65

NB-07 SF 1001–1009 S Central Ave 72 72c 50 47 3 Rail boot 60 280

SB-11 SF 3716 S Central Ave 72 74 51 48 1 Low-impact

frog — —

SB-23 SF S Central Ave and W Cody Dr

72 75 50 49 16 Low-impact frog — —

SB-42 SF


72 76 51 50 2 Low-impact frog — —

NB-A SC Arizona Summit Law School

78 66 40 40c 1 Rail boot 55 210

NB-B Court Maricopa County Justice Courts

78 67 41 41c 1 Rail boot 40 230

NB-C MD Salvation Army Adult Rehab Center

78 78c 43 53 1 Low-impact frog Rail boot

65 480

NB-G CH Revealed Word Church 78 78c 52 52c 1 Low-impact

frog — —

SB-N SC Phoenix Collegiate Academy

78 82 52 57 1 Low-impact frog — —

a ID identifies sensitive receivers as shown in the maps in Appendix F. NB = northbound side, SB = southbound side. b SF = single-family residential, MF = multifamily residential, Court = courthouse, MD = medical center, CH = church, SC = school c Levels are reported to the nearest decibel. These numbers represent fractional exceedances of less than 1 dB (still considered an impact).


6.0 POTENTIAL CONSTRUCTION NOISE AND VIBRATION

IMPACTS AND MITIGATION

6.1 CONSTRUCTION NOISE

The use of heavy equipment during project construction has the potential to result in substantial, yet temporary, increases in local noise levels along the corridor. The FTA Guidance Manual recommends using local construction noise limits, if possible. For the City of Phoenix, the municipal code is interpreted as having no specific noise limits that apply. As a result, the construction noise for this project should be examined in terms of the FTA guidance (shown in Table 19) for evaluating the potential community response to construction noise. The guidelines are based on an average Leq over a typical 8-hour workday. The FTA recommended limit of 80 dBA for the daytime Leq has been used in this assessment as the threshold for impact for residential areas.

TABLE 19: CONSTRUCTION NOISE GUIDELINES

Land Use Noise Limit,

8-hour Leq (dBA) Daytime Nighttime

Residential 80 70 Commercial 85 85 Industrial 90 90 Source: Federal Transit Administration (2006)

Construction noise levels depend on the number of pieces and type of equipment, their general condition, the amount of time each piece operates per day, the presence or lack of noise-attenuating features such as walls and berms and the location of the construction activities relative to the sensitive receivers. The majority of these variables are left to the discretion of the construction contractor selected by Valley Metro as the project approaches the construction phase. Therefore, it is not possible to accurately estimate construction noise levels at this conceptual design stage of the project. For a rough estimate of construction noise, the following describes a typical construction scenario. The construction of light rail track requires use of heavy earth-moving equipment, pneumatic tools, generators, concrete pumps and similar equipment. Table 20 shows the equipment likely to be used during the noisiest periods of track construction, the typical noise generated by this equipment, the usage factors and the estimated work-shift Leq. The combined work-shift Leq for the construction scenario shown in Table 20 is 84 dBA at a distance of 50 feet. Given that some residences along the corridor are within 50 feet of the alignment, it is clear that there is a high probability that the contractor would exceed the impact threshold of 80 dBA for the work-shift Leq. This analysis shows that impacts are likely unless the contractor is required to implement noise control measures when working near residences.


TABLE 20: PREDICTED CONSTRUCTION NOISE AT 50 FEET

Equipment Sound Level

at 50 feet Under Load

Source Usage Factor

(% Time Under Full Load)

Leq (8-hour Work Shift)

Earthmover (bulldozer, front-end loader, etc.) 82 dBA 40% 78 dBA

Mobile Crane 81 dBA 20% 74 dBA Dump Truck 76 dBA 40% 72 dBA Pneumatic Tools 85 dBA 30% 80 dBA Generator 78 dBA 40% 74 dBA Compressor 81 dBA 40% 77 dBA

Total 84 dBA

6.2 CONSTRUCTION VIBRATION

The primary concern regarding construction vibration is potential damage to structures. The thresholds for potential damage are much higher than the thresholds for evaluating potential annoyance used to assess impact from operational vibration. The FTA Guidance Manual limits for construction vibration for the various building categories, as defined in this table, are shown in Table 21. It is important to note that the vibration limits in Table 21 are the levels at which there is a risk for damage for each building category, not the level at which damage would occur. These limits should be viewed as criteria that should be used during the impact assessment phase to identify problem locations. Predicted vibration levels for different pieces of construction equipment are shown in Table 22. At a distance of 50 feet from buildings, the predicted vibration level for all pieces of equipment is below the damage risk criteria for even those buildings most susceptible to damage. At a distance of 25 feet, the vibration level from a vibratory roller is predicted to exceed the damage criteria for Building Categories III and IV. As mentioned, the criteria levels indicate where there is a risk for damage—not that actual damage would occur. Vibration generated from the vibratory roller could result in an adverse effect if it is operated within 25 feet of nonengineered timber or masonry buildings. Mitigation measures for construction vibration are presented in Section 6.4. In the event that other vibration-generating equipment must be used for a sustained period of time closer than 25 feet to sensitive receivers, the Construction Management Plan should also include measures to minimize those potential vibration impacts during construction. Three buildings listed on the Phoenix Historic Property Register in the project area need to be evaluated for potential damage from construction vibration. The Luhrs City Center includes the Luhrs Tower, as well as the Luhrs Building, both located on Jefferson Street between Central Avenue and First Street. A mixture of retail and office space currently occupies the Luhrs City Center. The Luhrs Tower is about 26 feet from the nearest track, and the Luhrs Building is about 36 feet from the nearest track. These Noise and Vibration Technical Report 76 March 2016 Environmental Assessment South Central Light Rail Extension

buildings in the Luhrs City Center have not been analyzed for operational impacts. The Barrister Place building is located at the southeast corner of Jefferson and First Streets. The building is currently vacant, but is expected to be redeveloped into a mixed-use space including residential and retail units. The Barrister Place building is about 21 feet from the nearest track. All buildings are considered historic skyscrapers in the Downtown Phoenix area and are Category I receivers. As discussed above, predicted vibration levels from construction equipment do not exceed the construction vibration limit for Category I or II receivers at 25 feet. No adverse effect from construction vibration is predicted for either of the Luhrs City Center buildings. The Barrister Place building is less than 25 feet from the proposed construction area; however, it is considered a Category I building, which has a high threshold for damage, and no adverse effect is predicted for this building. Although no adverse effect is predicted, both the Luhrs City Center and the Barrister Place building should be included as part of the preconstruction survey to document 2015 conditions and to identify any architectural features that may be susceptible to damage from vibration.

TABLE 21: CONSTRUCTION VIBRATION DAMAGE RISK CRITERIA

Building Category Peak Particle

Velocity (inches/second)

I. Reinforced-concrete, steel or timber (no plaster) 0.5 II. Engineered concrete and masonry (no plaster) 0.3 III. Nonengineered timber and masonry buildings 0.2 IV. Buildings extremely susceptible to vibration damage 0.12 Source: Federal Transit Administration (2006)

TABLE 22: CONSTRUCTION VIBRATION PREDICTIONS

Equipment Peak Particle

Velocity at 25 feet (inches/second)

Peak Particle Velocity at 50 feet (inches/second)

Vibratory roller 0.21 0.07 Hoe ram 0.09 0.03 Large bulldozer 0.09 0.03 Caisson drilling 0.09 0.03 Loaded trucks 0.08 0.03 Jackhammer 0.04 0.01 Small bulldozer 0.003 0.001


6.3 CONSTRUCTION NOISE MITIGATION

Listed below are some typical approaches to reducing noise levels associated with the construction phase of major projects. Requiring the contractor to employ these methods should leave the contractor with enough flexibility to perform the work without undue financial or logistical burdens while protecting adjacent noise-sensitive receivers from excessive construction noise levels.

• Avoid nighttime construction when possible. If nighttime construction is necessary, develop nighttime noise limits.

• Use specialty equipment with enclosed engines and/or high-performance mufflers.

• Locate equipment and staging areas as far from noise-sensitive receivers as possible.

• Limit unnecessary idling of equipment.

• Install temporary noise barriers. This approach can be particularly effective for stationary noise sources such as compressors and generators.

• Reroute construction-related truck traffic away from local residential streets.

• Avoid impact pile driving where possible. Where geological conditions permit, the use of drilled piles or a vibratory pile driver is generally quieter.

Specific measures to be employed to mitigate construction noise impacts should be developed by the contractor and presented in the form of a Noise Control Plan.

6.4 CONSTRUCTION VIBRATION MITIGATION

Construction-related vibration activities are unlikely to exceed the impact thresholds shown in Table 21. However, the following precautionary vibration mitigation strategies would be implemented to minimize the potential for damage to any structures in the corridor:

• Preconstruction Survey: The survey should include inspecting building foundations and taking photographs of preexisting conditions. The survey can be limited to buildings within 25 feet of high-vibration-generating construction activities. The only exception is if an important and potentially fragile historic resource is located within approximately 200 feet of construction, in which case it should be included in the survey.

• Vibration Limits: The FTA Guidance Manual suggests vibration limits in terms of peak particle velocity, ranging from 0.12 inches/second for “buildings extremely susceptible to vibration damage” to 0.5 inches/second for “Reinforced-concrete, steel or timber” buildings. The contract specifications should limit construction vibration to a maximum of 0.5 inches/second for all buildings in the corridor.

• Vibration Monitoring: The contractor should be required to monitor vibration at any building where vibratory rollers or similar high-vibration-generating equipment would be operated within 25 feet of buildings and at any location where complaints about vibration are received from building occupants.


• Alternative Construction Procedures: If high-vibration construction activities must

be performed close to structures, it may be necessary for the contractor to use an alternative procedure that produces lower vibration levels. Examples of high-vibration construction activities include the use of vibratory compaction or hoe rams next to sensitive buildings. Alternative procedures include use of nonvibratory compaction in limited areas and a concrete saw in place of a hoe ram to break up pavement.


7.0 REFERENCES

American Railway Engineering and Maintenance-of-Way Association (AREMA). 2010. AREMA C&S Manual. Part 3.2.61, Recommended Design Criteria for an Electronic Highway-Rail Grade Crossing Pedestrian Bell.

Federal Transit Administration (FTA) Office of Planning and Environment. 2006. Transit Noise and Vibration Impact Assessment. Document FTA-VA-90-1003-06. May. (Also referred to as FTA Guidance Manual.)

Valley Metro. 2010. Central Mesa LRT Extension Draft Environmental Assessment: Noise and Vibration Technical Report. November.


APPENDIX A. FUNDAMENTALS OF NOISE AND VIBRATION

Noise and Vibration Technical Report A-1 March 2016 Environmental Assessment South Central Light Rail Extension

NOISE FUNDAMENTALS

Sound is mechanical energy transmitted by pressure waves in a compressible medium such as air. Typically, noise is defined as unwanted or excessive sound. Sound can vary in intensity by over one million times within the range of human hearing. Therefore, a logarithmic scale, known as the decibel scale (dB), is used to quantify sound intensity and compress the scale to a more convenient range. Sound is characterized by both its amplitude and frequency (or pitch). The human ear does not hear all frequencies equally. In particular, the ear deemphasizes low and very high frequencies. The A-weighted decibel scale (dBA) better approximates the sensitivity of human hearing. On this scale, the human range of hearing extends from approximately 3 dBA to around 140 dBA. As a point of reference, Figure A-1 includes examples of A-weighted sound levels from common indoor and outdoor sounds. Using the decibel scale, sound levels from two or more sources cannot be directly added together to determine the overall sound level. Rather, the combination of two sounds at the same level yields an increase of 3 dB. The smallest recognizable change in sound level is approximately 1 dB. A 3 dB increase in the A-weighted sound level is considered generally perceptible, whereas a 5 dB increase is readily perceptible. A 10 dB increase is judged by most people as an approximate doubling of the perceived loudness. The two primary factors that reduce levels of environmental sounds are (1) increasing the distance between the sound source and the receiver and (2) having intervening obstacles such as walls, buildings or terrain features that block the direct path between the sound source and the receiver. Factors that act to make environmental sounds louder include moving the sound source closer to the receiver, sound enhancements caused by reflections and focusing caused by various meteorological conditions. The following are brief definitions of the measures of environmental noise used in this report: Maximum Sound Level (Lmax): Lmax is the maximum sound level that occurs during an event such as a light rail passing. For this analysis, Lmax is defined as the maximum sound level using the slow setting on a standard sound level meter. Equivalent Sound Level (Leq): Environment sound fluctuates constantly. The equivalent sound level (Leq) is the most common means of characterizing community noise. Leq represents a constant sound that, over a specified period of time, has the same sound energy as the time-varying sound. Leq is used by FTA to evaluate noise impacts at institutional land uses, such as schools, churches and libraries, from proposed transit projects. Day-Night Sound Level (Ldn): Ldn is a 24-hour Leq with an adjustment to reflect the greater sensitivity of most people to nighttime noise. The adjustment is a 10 dB penalty for all sound that occurs between the hours of 10 p.m. to 7 a.m. The effect of the penalty is that, when calculating Ldn, any event that occurs during the nighttime is equivalent to ten occurrences of the same event during the daytime. Ldn is the most common measure of total community noise over a 24-hour period and is used by FTA to evaluate residential noise impacts from proposed transit projects.


Lxx: This is the percentage of time a sound level is exceeded during the measurement period. For example, the L99 is the sound level exceeded 99 percent of the measurement period. For a 1-hour period, L99 is the sound level exceeded for all except 36 seconds of the hour. L1 represents typical maximum sound levels, L33 is approximately equal to Leq when free-flowing traffic is the dominant noise source, L50 is the median sound level and L99 is close to the minimum sound level. Sound Exposure Level (SEL): SEL is a measure of the acoustic energy of an event such as a train passing. In essence, the acoustic energy of the event is compressed into a 1-second period. SEL increases as the sound level of the event increases and as the duration of the event increases. It is often used as an intermediate value in calculating overall metrics such as Leq and Ldn. Sound Transmission Class (STC): STC ratings are used to compare the sound insulating effectiveness of different types of noise barriers, including windows, walls, etc. Although the amount of attenuation varies with frequency, the STC rating provides a rough estimate of the transmission loss from a particular window or wall.

FIGURE A-1: TYPICAL OUTDOOR AND INDOOR NOISE LEVELS

VIBRATION FUNDAMENTALS

One potential community impact from the proposed project is vibration that is transmitted from the tracks through the ground to adjacent houses. This is referred to as groundborne vibration. When evaluating human response, groundborne vibration is


expressed in terms of decibels using the root mean square (RMS) vibration velocity. RMS is defined as the average of the squared amplitude of the vibration signal. To avoid confusion with sound decibels, the abbreviation VdB is used for vibration decibels. All vibration decibels in this report use a decibel reference of 1 micro-inch/second (µin/sec).1 The potential adverse impacts of rail transit groundborne vibration are as follows: Perceptible Building Vibration: The vibration of the floor or other building surfaces that the occupants feel. Experience shows that the threshold of human perception is around 65 VdB and that vibration that exceeds 75 to 80 VdB is perceived as intrusive and annoying to occupants. Rattle: The building vibration can cause rattling of items on shelves and hangings on walls, and various rattle and buzzing noises from windows and doors. Reradiated Noise: The vibration of room surfaces radiates sound waves that are audible to humans (groundborne noise). Groundborne noise sounds like a low-frequency rumble. Usually, for a surface rail system such as the proposed light rail, the groundborne noise is masked by the normal airborne noise radiated from the transit vehicle and the rails. Damage to Building Structures: Although it is conceivable that vibration from a light rail system can damage fragile buildings, the vibration from rail transit systems is one to two orders of magnitude below the most restrictive thresholds for preventing building damage. Hence the vibration impact criteria focus on human annoyance, which occurs at much lower amplitudes than does building damage. Vibration is an oscillatory motion that is described in terms of the displacement, velocity or acceleration of the motion. The response of humans to vibration is very complex. However, the general consensus is that for the vibration frequencies generated by light rail, human response is best approximated by the vibration velocity level. Therefore, this study uses vibration velocity to describe light rail-generated vibration levels. Figure A-2 shows typical vibration levels from rail and nonrail sources as well as the human and structure response to such levels. Although there is relatively little research into human and building response to groundborne vibration, there is substantial experience with vibration from rail systems. In general, the collective experience indicates that: It is rare that groundborne vibration from transit systems results in building damage (even minor cosmetic damage). Therefore, the primary consideration is whether or not the vibration is intrusive to building occupants or interferes with interior activities or machinery. The threshold for human perception is approximately 65 VdB. Vibration levels in the range of 70 to 75 VdB often are noticeable but acceptable. Beyond 80 VdB, vibration levels are considered unacceptable.

1 One µin/sec = 10 -6 in/sec


For human annoyance, there is a relationship between the number of daily events and the degree of annoyance caused by groundborne vibration. The FTA Guidance Manual includes an 8 VdB higher impact threshold if there are fewer than 30 events per day and a 3 VdB higher threshold if there are fewer than 70 events per day.

FIGURE A-2: TYPICAL VIBRATION LEVELS

Often it is necessary to determine the contribution at different frequencies when evaluating vibration or noise signals. The 1/3-octave band spectrum is the most common procedure used to evaluate frequency components of acoustic signals. The term octave is borrowed from music, where it refers to a span of eight notes. The ratio of the highest frequency to the lowest frequency in an octave is 2:1. For a 1/3-octave band spectrum, each octave is divided into three bands, where the ratio of the lowest frequency to the highest frequency in each 1/3-octave band is 21/3:1 (1.26:1). An octave consists of three 1/3 octaves. The 1/3-octave band spectrum of a signal is obtained by passing the signal through a bank of filters. Each filter excludes all components except those that are between the upper and lower range of one 1/3-octave band.


APPENDIX B. FORCE DENSITY MEASUREMENT RESULTS

Noise and Vibration Technical Report B-1 March 2016 Environmental Assessment South Central Light Rail Extension

FORCE DENSITY MEASUREMENT RESULTS

This appendix provides the results of the light rail vibration testing that was performed at the Valley Metro Starter Line. The equipment (vehicles and track design) that is used for the Starter Line is similar to the equipment that would be used on the South Central Line. FDL measurements were performed in Phoenix along the Light Rail Starter Line as a part of the Valley Metro Rail Mesa Extension Noise and Vibration Technical Report (2010). The test was performed at 5552 Washington Street at a section along tangent track (Figure B-1). A single train was operated on the near track (NT) at controlled speeds. Following is a summary of the tests performed to derive a force density for the Valley Metro Starter Line: 1. Light rail vibration was measured at five distances from the track. The

accelerometers were placed at distances ranging from 50 to 200 feet north of the westbound track, which was the NT. The eastbound track was 12 feet south of the westbound track.

2. The root mean square (rms) light rail vibration at each measurement position was determined on a 1/3 octave band basis over the frequency range of 5 to 315 Hz. The measured 1/3 octave band rms vibration levels were adjusted to obtain the maximum 1-second rms value for the light rail vibration.

3. Transfer mobility was measured using a line of impacts. The impact line consisted of 11 locations separated by 15 feet for a total length of 150 feet. The same accelerometer positions used for the train vibration were used for the transfer mobility tests. The impact line was located in the center of the NT. The point source transfer mobilities at the 11 impact points were combined to obtain the line source transfer mobility (LSTM) at each accelerometer position.

4. The FDL from each train passby was calculated as the difference between the measured train vibration level and the LSTM. The vibration data from frequency bands where the light rail vibration did not exceed the background vibration was not used in the FDL calculation.

5. At each accelerometer position, the FDL estimates for each vehicle and track were energy averaged.

6. The final FDLs for the two vehicles were estimated by using the maximum of the energy-averaged force densities of all sensor positions. This approach was taken to ensure that the final FDLs would be an upper bound of the true FDL and would tend to over predict light rail vibration levels rather than under predict vibration levels.


FIGURE B-1: AERIAL VIEW OF FDL MEASUREMENT LOCATION

TRANSFER MOBILITY TESTS

The measured transfer mobility and coherence functions from the propagation tests are given in Figure B-2. The transfer mobilities were measured using accelerometers mounted at distances of 50, 75, 100, 150 and 200 feet from the westbound track centerline. The impact line was located on the track centerline. As expected, the transfer mobilities decreased with distance from the impact line. There was good coherence over the 16 to 250 Hz range at all except the 125-foot measurement position. The transfer mobility at 125 feet had poor coherence above 80 Hz.


FIGURE B-2: LSTM AND COHERENCE, WASHINGTON STREET

LIGHT RAIL VEHICLE VIBRATION

Light rail vibration was measured at the same locations as the transfer mobility measurements. Two tracks were at the measurement location. The westbound track was the NT and the eastbound track centerline was 12 feet from the westbound track centerline. As discussed earlier, the vibration sensors were located at 50, 75, 100, 150 and 200 feet from the westbound track centerline and were identified as Channels 2, 3, 4, 5 and 6, respectively. During the measurement period, 16 total passbys were measured, two passbys at speeds of 5, 10, 15, 20, 25, 30, 35 and 40 mph each. The light rail speeds were verified with a radar gun. The measurement results are shown in Figure B-3. Observations from the light rail vibration results are:

• Train vibrations at various speeds are reasonably well-grouped; however, there is as much as a 10-dB difference between the maximum and minimum events.


FIGURE B-3: MEASURED TRAIN VIBRATION AT VARYING SPEEDS


FORCE DENSITY

Figure B-4 shows the average FDL at each speed from the Washington Street measurements. The FDL at each speed are reasonably grouped within a 5-dB range. The exception is at the 50-foot position, which has high levels below 31.5 Hz. These levels are not included in the average FDL for these speeds. The final FDL for each train speed is shown in Figure B-5.

FIGURE B-4: AVERAGE WASHINGTON STREET LIGHT RAIL FORCE DENSITY LEVELS


FIGURE B-5: METRO LRV FORCE DENSITY LEVELS VERSUS SPEED


COMPARISON TO FDL USED IN CAPITOL I-10 PROJECT

Additional measurements of the Valley Metro LRV FDL were made as a part of the Capitol/I-10 West Light Rail Extension. These measurements were conducted by consulting firm Harris, Miller, Miller, and Hanson Inc. (HMMH), during 2013. The results of these FDL tests were reported in the Capitol/I-10 West Light Rail Extension Noise and Vibration Technical Report, issued June 2015 (Valley Metro 2015). The 2013 FDL measurements (Valley Metro 2015) were conducted at the same Washington Street site as in 2009. The results from both the 2009 and 2013 FDL measurements are shown in Figure B-6. This shows that above 25 Hz there is good agreement, with less than a 3-dB difference in any of the high frequency 1/3 octave bands. There is also a similar peak of 40 dB at 80 Hz. There is a discrepancy of about 5 dB at frequencies lower than 25 Hz. The groundborne vibration propagation along the South Central Light Rail Extension is most efficient at frequencies between 25 Hz and 80 Hz; therefore, this moderate discrepancy would not play a significant role in predicting impacts.

FIGURE B-6: COMPARISON OF WASHINGTON STREET FDL MEASURED IN 2009 AND 2013


APPENDIX C. NOISE SOURCE LEVEL

Noise and Vibration Technical Report C-1 March 2016 Environmental Assessment South Central Light Rail Extension

NOISE SOURCE LEVEL

For the South Central Light Rail Extension noise analysis, the Lmax measurements performed on the Valley Metro Starter Line (light rail embedded track) were used as the reference noise. The noise measurements from the Valley Metro Starter Line are documented in the Noise and Vibration Appendix of the Final Environmental Assessment for the Central Mesa LRT Extension, May 2011. The following is a summary of the testing and results:

• Noise measurements of train passbys were performed at controlled speeds after revenue hours on the Valley Metro Starter Line. Measurements were made at distances of 50, 100 and 200 feet from the near track and at speeds of 5 to 40 mph in increments of 5 mph. The reference level of 77 dBA at 50 feet for train speeds of 35 mph was derived from these tests.


APPENDIX D. VIBRATION PROPAGATION TEST RESULTS

Noise and Vibration Technical Report D-1 March 2016 Environmental Assessment South Central Light Rail Extension

VIBRATION PROPAGATION TEST RESULTS

This appendix provides photographs of the vibration propagation test sites, measured LSTM and coherence at each site and the best-fit coefficients derived from the measured LSTM at each site. Maps of test locations in relation to sensitive receivers are shown in Appendix F. This appendix is organized as follows:

• Photographs of the vibration propagation sites

• Aerial diagrams of the vibration propagation sites

• Measured LSTM and coherence

• Table of coefficients for the best-fit curves


PHOTOGRAPHS OF VIBRATION PROPAGATION SITES

FIGURE D-1: VIBRATION PROPAGATION SITE V-1



P.C.: Google Earth


TEST DIAGRAMS OF VIBRATION SITES

Provided in this section are diagrams of the vibration propagation test at each site. The yellow Xs indicate where the drop-weight hit the ground. The circles with A# in them indicate where vibration sensors (accelerometers) were placed. The solid yellow lines indicate the imaginary impact line and line of accelerometers. The impact line is intended to simulate a line-source train vibration. The line of accelerometers is used to derive the LSTM quantity as a function of distance from the line-source.

FIGURE D-5: AERIAL VIEW OF VIBRATION PROPAGATION SITE V-1


MEASURED LSTM AND COHERENCES AT EACH SITE

FIGURE D-9: MEASURED LSTM AND COHERENCE AT SITE V-1


LSTM COEFFICIENTS AND BEST-FIT DATA FOR EACH SITE

TABLE D-1: LINE SOURCE TRANSFER MOBILITY COEFFICIENTS, SITE V-1

Frequency A B C 6.3 17.2 –9.4 — 8 25.9 –13.7 — 10 29.0 –12.9 — 12.5 43.5 –17.3 — 16 53.2 –19.1 — 20 72.1 –26.2 — 25 78.1 –27.5 — 31.5 86.2 –32.3 — 40 80.3 –30.3 — 50 67.8 –25.8 — 63 61.9 –25.2 — 80 63.9 –29.3 — 100 61.3 –30.8 — 125 58.6 –32.3 — 160 37.5 –25.4 — 200 21.3 –21.1 — 250 13.6 –16.6 — 315 12.8 –16.1 —

FIGURE D-13: SITE V-1 BEST-FIT LINE TRANSFER MOBILITY



Frequency A B C 6.3 8.87 –3.70 — 8 13.98 –5.71 — 10 27.59 –9.90 — 12.5 25.07 –3.29 — 16 33.61 –3.70 — 20 42.22 –6.39 — 25 24.08 18.84 –7.52 31.5 23.13 24.85 –9.86 40 5.76 45.20 –15.72 50 33.88 25.87 –13.66 63 54.93 4.55 –9.60 80 34.56 21.00 –13.83 100 4.50 46.71 –21.03 125 30.24 15.75 –14.04 160 74.00 –35.30 –1.22 200 66.77 –36.86 — 250 72.69 –42.99 — 315 72.53 –44.84 —

FIGURE D-14: SITE V-2 BEST-FIT LINE SOURCE TRANSFER MOBILITY



Frequency A B C 6.3 13.09 –6.30 — 8 35.85 –18.76 — 10 37.74 –18.06 — 12.5 35.02 –10.94 — 16 34.93 –4.49 — 20 44.52 –5.99 — 25 57.86 –10.88 — 31.5 72.42 –17.33 — 40 74.72 –18.12 — 50 85.57 –25.19 — 63 87.72 –29.96 — 80 81.33 –30.70 — 100 79.71 –32.04 — 125 75.10 –31.99 — 160 76.18 –35.29 — 200 65.76 –33.02 — 250 32.00 –16.12 — 315 20.02 –12.29 —

FIGURE D-15: SITE V-3 BEST-FIT LINE TRANSFER MOBILITY



Frequency A B C 6.3 23.28 –7.71 — 8 28.03 –7.69 — 10 35.25 –7.94 — 12.5 34.66 –5.56 — 16 36.86 –5.25 — 20 45.56 –8.48 — 25 52.50 –9.69 — 31.5 66.11 –16.53 — 40 78.89 –23.25 — 50 90.60 –30.87 — 63 81.96 –28.37 — 80 77.74 –28.82 — 100 79.24 –33.20 — 125 77.00 –36.54 — 160 103.74 –55.60 — 200 109.54 –63.07 — 250 78.55 –48.77 — 315 43.15 –31.39 —

FIGURE D-16: SITE V-4 BEST-FIT LINE SOURCE TRANSFER MOBILITY


APPENDIX E. AMBIENT NOISE AND VIBRATION

MEASUREMENT SITES

Noise and Vibration Technical Report E-1 March 2016 Environmental Assessment South Central Light Rail Extension

AMBIENT NOISE MEASUREMENT SITES

This section provides the detailed ambient noise data for the sites discussed in Section 4.0. All data shown here were collected in September 2015. Maps of measurement locations in relation to sensitive receivers are shown in Appendix F. LT-1: Superior Court of Arizona in Maricopa County – Old Courthouse Measured Ldn: 67.8 dBA

FIGURE E-1: LT-1, 24-HOUR AMBIENT NOISE TIME HISTORY


LT-2: Central Avenue and Buckeye Road

Measured Ldn: 70.1 dBA



LT-3: Central Avenue and Southgate Avenue




LT-4: South Mountain Mortuary




ST-1: Hotel Palomar

Measured Leq

Noise: 68.6 dBA

Vibration: 55.2 VdB

FIGURE E-5: ST-1, 1-HOUR AMBIENT NOISE TIME HISTORY

FIGURE E-6: ST-1, 1-HOUR AMBIENT VIBRATION TIME HISTORY


ST-2: 1st Avenue and Sherman Street

Measured Leq

Noise: 68.6 dBA

Vibration: 63.2 VdB




ST-3: 1st Street and Durango Street

Measured Leq

Noise: 63.2 dBA



ST-4: Rio Salado Habitat Restoration Area (south of river)

Measured Leq

Noise: 62.6 dBA

Vibration: 47.6 VdB

FIGURE E-10: ST-4, 30-MINUTE AMBIENT NOISE TIME HISTORY

FIGURE E-11: ST-4, 30-MINUTE AMBIENT VIBRATION TIME HISTORY


ST-4A: Rio Salado Audubon Center – Near Building

Measured Leq

Noise: 56.6 dBA

FIGURE E-12: ST-4A, 1-HOUR AMBIENT NOISE TIME HISTORY


ST-5: Central Avenue and Cody Drive

Measured Leq

Noise: 69.3 dBA

Vibration: 53.9 VdB




ST-6: 5425 S. Central Avenue

Measured Leq

Noise: 73.0 dBA

Vibration: 50.0 VdB

P.C: Google Earth




ST-7: Cigna Medical Group

Measured Leq

Noise: 71.1 dBA

Vibration: 58.4 VdB




ST-8: Saint Catherine of Siena Catholic School

Measured Leq

Noise: 70.5 dBA



ST-9: Baseline Road between 2nd and 3rd Avenue

Measured Leq

Noise: 70.1 dBA

FIGURE E-20: ST-9, 20-MINUTE AMBIENT NOISE TIME HISTORY


The following ambient vibration measurements were taken at the vibration propagation test sites. Measurements were taken during off-peak hours. Further information on those locations is in Appendix D. V-1: Maricopa County Superior Courthouse: South Court Tower

Measured Leq: 40 ft

Vibration: 46.9 VdB

FIGURE E-21: V-1 AMBIENT VIBRATION TIME HISTORY

V-2: 1020 South Central Avenue

Measured Leq: 43 ft

Vibration: 43.2 VdB



V-3: 4216 South Central Avenue

Measured Leq: 40 ft

Vibration: 53.2 VdB


V-4: South Mountain Mortuary

Measured Leq: 40 ft

Vibration: 54.2 VdB



APPENDIX F. SENSITIVE RECEIVER INVENTORY

Noise and Vibration Technical Report F-1 March 2016 Environmental Assessment South Central Light Rail Extension

SENSITIVE RECEIVER INVENTORY

Table F-1 lists the sensitive receivers potentially affected by the light rail operations/construction and also the TPSSs. Figure F-1 shows the area labels along the northern portion of the alignment, and Figure F-2 shows the area labels along the southern portion of the alignment. Figures F-3 to F-11 show the sensitive receivers along the proposed alignment by areas of the alignment.


TABLE F-1: SENSITIVE RECEIVER INVENTORY

Area ID Location Distance to Near Track

(feet) FTA Category Typea

Extra Elements

Included in Analysisb

No. of Units

Downtown NB-01 Hotel Palomar Phoenix 17 2 – residential HT X 190c

Downtown NB-02 Barrister Place (potential multiuse redevelopment with residential component) 21 2 – residential MF X 35c

Downtown NB-03 Luhrs City Center Marriott (under construction) 43 2 – residential HT X 80c

Lincoln to Buckeye NB-04 700–722 S 1st St 198 2 – residential SF X, TB 10

Lincoln to Buckeye NB-05 734–800 S 1st St and 12 E Hadley St 148 2 – residential SF X 7

Lincoln to Buckeye NB-06 900–922 S 1st St 208 2 – residential SF — 7

Lincoln to Buckeye NB-07 1001–1009 S Central Ave 54 2 – residential SF TB 3

Lincoln to Buckeye NB-08 1000–1022 S 1st St 210 2 – residential SF TB 13

Buckeye to I-17 NB-09 1706–1712 S 1st St 181 2 – residential SF — 3 Buckeye to I-17 NB-10 1701–1725 S 1st St 340 2 – residential SF — 8 I-17 to Broadway (MLK) NB-11 11–13 E Elwood St 113 2 – residential SF X, TB 3

I-17 to Broadway (MLK) NB-12 15–19 E Elwood St 228 2 – residential SF X, TB 2

I-17 to Broadway (MLK) NB-13 7–13 E Raymond St 122 2 – residential SF X, TPSS 2

I-17 to Broadway (MLK) NB-14 17–25 E Raymond St and 32 E Raymond

St 239 2 – residential SF X, TPSS 4

I-17 to Broadway (MLK) NB-15 15 E Jones Ave and 20–22 E Southgate

Ave 240 2 – residential SF TB 3





Extra Elements


No. of Units

I-17 to Broadway (MLK) NB-16 14 E Southgate Ave 180 2 – residential SF TB 1

I-17 to Broadway (MLK) NB-17 17–27 E Southgate Ave 176 2 – residential SF — 3

I-17 to Broadway (MLK) NB-18 18–22 E Riverside St 212 2 – residential SF TB 2

I-17 to Broadway (MLK) NB-19 23–29 E Riverside St 263 2 – residential SF TB 6

Broadway (MLK) to Roeser NB-20 16 E Cody Drive 341 2 – residential SF X 1

Roeser to Southern NB-21 25 E Roeser Rd 305 2 – residential SF TB 1

Roeser to Southern NB-22 5403 S Central Ave, 2nd+ rows 137 2 – residential SF TB 4

Roeser to Southern NB-23 5615 S Central Ave, 1st row 108 2 – residential SF X, TB, TPSS 3

Roeser to Southern NB-24 5615 S Central Ave, 2nd row 214 2 – residential SF X, TPSS 6

Roeser to Southern NB-25 40 E Hidalgo Ave 151 2 – residential SF X 1

Southern to Vineyard NB-26 22–99 E Lynne Lane 227 2 – residential SF TB 3

Southern to Vineyard NB-27 6210–6232 S 1st St 248 2 – residential SF TB 4

Southern to Vineyard NB-28 6234–6240 S 1st St and 20–22 E Alta Vista

Rd 238 2 – residential SF TB 4

Southern to Vineyard NB-29 19 E St. Catherine Ave 257 2 – residential SF — 1





Extra Elements


No. of Units

Southern to Vineyard NB-30 14–26 E St. Anne Ave and 25 E St.

Catherine Ave 175 2 – residential SF — 4

Southern to Vineyard NB-31 15 E St. Anne Ave 191 2 – residential SF — 1

Southern to Vineyard NB-32 19–25 E St. Anne Ave and

16–26 E St. Charles Ave 172 2 – residential SF — 5

Southern to Vineyard NB-33 6645 S Central Ave 145 2 – residential SF TB 1

Southern to Vineyard NB-34 21–25 E St. Charles Ave 239 2 – residential SF TB 2

Vineyard to Baseline NB-35 8–29 E Greenway Rd 174 2 – residential SF — 3

Vineyard to Baseline NB-36 7001 S Central Ave and 14 E Carter Rd 96 2 – residential SF TPSS 2

Vineyard to Baseline NB-37 28–31 E Carter Rd 301 2 – residential SF — 2

Roeser to Southern NB-38 Westview Apartments on Sunland 350 2 – residential MF TPSS 28c

Buckeye to I-17 NB-39 Salvation Army Adult Rehab Center – residential 68 2 – residential MF X, TB, TPSS 38c

Lincoln to Buckeye SB-01 704–710 S 1st Ave 110 2 – residential SF TB 3

Lincoln to Buckeye SB-02 113–115 W Grant St 221 2 – residential SF TB 3

Lincoln to Buckeye SB-03 801–821 S 1st Ave and 16 W Hadley St 99 2 – residential SF X, TPSS 6

Lincoln to Buckeye SB-04 1010 S Central Ave 71 2 – residential SF TB 1





Extra Elements


No. of Units

Lincoln to Buckeye SB-05 1001–1021 S 1st Ave and 21 W Tonto St 231 2 – residential MF TB 10c

Buckeye to I-17 SB-06 1105–1115 S 1st Ave 246 2 – residential SF TB 3 Buckeye to I-17 SB-07 1217–1221 S 1st Ave 303 2 – residential SF TB 2

Buckeye to I-17 SB-08 1301–1321 S 1st Ave and 2–98 W Papago St 215 2 – residential SF TB 10

I-17 to Broadway (MLK) SB-09 16–18 W Fulton St 155 2 – residential SF X 2

I-17 to Broadway (MLK) SB-10 22–30 W Fulton St 265 2 – residential SF X 5

I-17 to Broadway (MLK) SB-11 3716 S Central Ave 65 2 – residential SF X, TPSS 1

I-17 to Broadway (MLK) SB-12 25 W Fulton St and various on W West Rd 301 2 – residential SF X 7

I-17 to Broadway (MLK) SB-13 20–28 W Illini St 257 2 – residential MF — 8c

I-17 to Broadway (MLK) SB-14 11–29 W Illini St and 32 W Jones Ave 280 2 – residential SF — 4

I-17 to Broadway (MLK) SB-15 15, 20 W Jones Ave 175 2 – residential SF TB 2

I-17 to Broadway (MLK) SB-16 35 W Jones Ave and 20–34 W Southgate

Ave 270 2 – residential SF TB 4

I-17 to Broadway (MLK) SB-17 19–35 W Southgate Ave and

20–32 W Riverside St 261 2 – residential SF — 5

I-17 to Broadway (MLK) SB-18 31 W Riverside St and 30–34 W Pueblo

Ave 366 2 – residential SF — 3

I-17 to Broadway (MLK) SB-19 4216 S Central Ave 107 2 – residential SF TB 2





Extra Elements


No. of Units

Broadway (MLK) to Roeser SB-20 11 W Corona Ave and 20 W Marguerite

Ave 198 2 – residential SF — 2

Broadway (MLK) to Roeser SB-21 21–29 W Corona Ave and

30–106 W Marguerite Ave 300 2 – residential SF — 6

Broadway (MLK) to Roeser SB-22 30–32 W Tamarisk Ave 343 2 – residential SF TB 2

Broadway (MLK) to Roeser SB-23 S Central Ave and W Cody Dr, 1st and

2nd rows 68 2 – residential SF X, TB 16

Broadway (MLK) to Roeser SB-24 S Central Ave and W Cody Dr, 3rd and

4th rows 265 2 – residential SF X 26

Broadway (MLK) to Roeser SB-25 1008 W Roeser Rd 382 2 – residential SF TB 1

Roeser to Southern SB-26 17–23 W Roeser Rd, 100 W Grove St,

5223 S 1st Ave 187 2 – residential SF TB 4

Roeser to Southern SB-27 101–107 W Roeser Rd, 102–108 W Grove

St 312 2 – residential SF TB 4

Roeser to Southern SB-28 5227–5249 S 1st Ave 182 2 – residential SF TB 5

Roeser to Southern SB-29 101 W Grove St, 102 W Chambers St 354 2 – residential SF TB 2

Roeser to Southern SB-30 5403–5421 S 1st Ave 199 2 – residential SF — 5

Roeser to Southern SB-31 101 W Chambers St, 102 W Bowker St 348 2 – residential SF — 2

Roeser to Southern SB-32 5423 S 1st Ave, 101 W Bowker St,

20–24 W Sunland Ave 200 2 – residential SF X, TB 4

Roeser to Southern SB-33 103–107 W Bowker St,

104–106 W Sunland Ave 329 2 – residential SF X 4





Extra Elements


No. of Units

Roeser to Southern SB-34 105 W Sunland Ave 354 2 – residential SF X, TB 2

Southern to Vineyard SB-35 6202–6222 S 1st Ave 371 2 – residential SF — 5

Southern to Vineyard SB-36 6224–6244 S 1st Ave 371 2 – residential SF TB 5

Southern to Vineyard SB-37 17–107 W Alta Vista Rd,

16–108 W St. Catherine Ave 236 2 – residential MF TB 17c

Southern to Vineyard SB-38 27–35 W St. Charles Ave 199 2 – residential SF TB 2

Vineyard to Baseline SB-39 6810 S Central Ave, 90 W Maldonado Pl 228 2 – residential SF TB 3

Vineyard to Baseline SB-40 22–104 W Carson Rd, 17–29 W Carson Rd 246 2 – residential MF — 13c

Vineyard to Baseline SB-41 26–34 W Fremont Rd, 25 W Fremont Rd 249 2 – residential SF TB 5

Vineyard to Baseline SB-42 7252 S Central Ave, 1st row, and 7246 S

Central Ave 64 2 – residential SF X, TB 2

Vineyard to Baseline SB-43 7252 S Central Ave, 2nd row 316 2 – residential SF X, TB 1

Downtown (N) SB-44 825 N 2nd Ave 338 2 – residential MF X 20c Downtown (N) SB-45 631 N 1st Ave 315 2 – residential HT X 80c Downtown NB-A Arizona Summit Law School 52 3 – institutional SC X 1 Downtown NB-B Maricopa County Justice Courts 33 3 – institutional Court X 1 Buckeye to I-17 NB-C Salvation Army Adult Rehab Center 36 3 – institutional SC X, TB, TPSS 1 I-17 to Broadway (MLK) NB-D Rio Salado Habitat Restoration Area 34 3 – institutional Habitat TB 1





Extra Elements


No. of Units

I-17 to Broadway (MLK) NB-E Rio Salado Habitat Restoration Area –

Audubon Center (south of river) 34 3 – institutional Habitat CB 1

I-17 to Broadway (MLK) NB-E1 Rio Salado Audubon Center buildings –

includes classroom 290 3 – institutional SC CB, TB 1

I-17 to Broadway (MLK) NB-F Revealed Word Church 49 3 – institutional CH X, TPSS 1

Broadway (MLK) to Roeser NB-G Espiritu School Chapel and Offices 91 3 – institutional CH TB 1

Broadway (MLK) to Roeser NB-H Espiritu Schools 304 3 – institutional SC TB 1

Roeser to Southern NB-I Central DI Ministries 148 3 – institutional CH X, TB 1

Southern to Vineyard NB-J Southside Animal Hospital 95 3 – institutional HP TB 1

Southern to Vineyard NB-K Saint Catherine of Siena Catholic School 110 3 – institutional SC TB 1

Vineyard to Baseline NB-L South Mountain Mortuary 68 3 – institutional CH TB, TPSS 1

Downtown (N) NB-M Christian Science First Church 357 3 – institutional CH X 1

Downtown SB-A Superior Court of Arizona in Maricopa County 95 3 – institutional Court X 1

Downtown SB-B Maricopa East Court Building/Law Library 51 3 – institutional Court X, TB 1 Downtown SB-C Maricopa County Superior Courthouse 130 3 – institutional Court TB 1 Lincoln to Buckeye SB-D Friendly House – Adult Education and

Workforce Development 285 3 – institutional SC X 1

Lincoln to Buckeye SB-E Saint Anthony Catholic Church 210 3 – institutional CH — 1





Extra Elements


No. of Units

I-17 to Broadway (MLK) SB-F Iglesia Apostolica Cristiana 207 3 – institutional CH X, TB 1

I-17 to Broadway (MLK) SB-G Preston Funeral Home 49 3 – institutional CH X, TPSS 1

Broadway (MLK) to Roeser SB-H Preschool 134 3 – institutional SC TB 1

Roeser to Southern SB-I Phoenix Collegiate Academy 48 3 – institutional SC X, TB 1

Roeser to Southern SB-J Ocotillo Library 381 3 – institutional LB — 1

Southern to Vineyard SB-K Saint Catherine of Siena Roman Catholic

Church 106 3 – institutional CH TB 1

Southern to Vineyard SB-L Southern Baptist Temple 80 3 – institutional CH — 1

Southern to Vineyard SB-M St. John Bosco Chapel/St. Catherine of

Siena Catholic Preschool 110 3 – institutional SC — 1

Vineyard to Baseline SB-N Cigna Medical Group 142 3 – institutional MD X, TB, TPSS 1

Downtown (N) SB-O Phoenix College Downtown 180 3 – institutional SC X 1 a SF = single-family, MF = multifamily, HT = hotel, SC = school, CH = church, MD = medical, Court = courthouse, LB = library, Habitat = habitat restoration area b Extra elements are included in the analysis, indicated with the following letter codes: X = crossover, CB = crossing bells, TB = train bells (at intersections or stations), TPSS = traction power substation unit c Number of rooms/units estimated to be potentially exposed to noise.


FIGURE F-1: ALIGNMENT SECTIONS – NORTH


FIGURE F-2: ALIGNMENT SECTIONS – SOUTH


FIGURE F-3: SENSITIVE RECEIVERS – DOWNTOWN


FIGURE F-4: SENSITIVE RECEIVERS – LINCOLN TO BUCKEYE


FIGURE F-5: SENSITIVE RECEIVERS – BUCKEYE TO I-17


FIGURE F-6: SENSITIVE RECEIVERS – I-17 TO ELWOOD


FIGURE F-7: SENSITIVE RECEIVERS – ELWOOD TO BROADWAY (MLK)


FIGURE F-8: SENSITIVE RECEIVERS –BROADWAY (MLK) TO ROESER


FIGURE F-9: SENSITIVE RECEIVERS – ROESER TO SOUTHERN


FIGURE F-10: SENSITIVE RECEIVERS – SOUTHERN TO VINEYARD


FIGURE F-11: SENSITIVE RECEIVERS – VINEYARD TO BASELINE


APPENDIX G. VIBRATION MITIGATION FOR SWITCHES

Noise and Vibration Technical Report G-1 March 2016 Environmental Assessment South Central Light Rail Extension

VIBRATION MITIGATION FOR SWITCHES

The banging that occurs when transit car wheels pass through switches is generally found to increase groundborne vibration levels at locations less than about 15 m from the switch by 10 decibels. Almost all of the increase in groundborne vibration and airborne noise occurs as the wheels pass through frogs. There are several alternatives to typical rail-bound manganese (RBM) frogs that will result in lower vibration and noise levels: RBM frogs: The common rail-bound manganese (RBM) frog is designed for main line freight track but is often used on transit systems. Wheel impacts as wheels cross the gap in the rail and when wheels hit the frog point typically increase noise levels by approximately 6 dBA and vibration levels by approximately 10 VdB. The actual increase will depend on the condition of the frog, how smoothly the wheel load is transferred from one side of the rail gap to the other, whether the movement over the frog is a straight-through or diverting move and the distance from the frog. Conceptually, higher number frogs have a smaller angle between the rails and the transition over the gap is distributed over a greater distance, so the additional noise and vibration levels should be lower. We are not aware of any measurement results that confirm that higher number frogs generate less noise and vibration than lower number frogs. Monoblock frogs: Monoblock frogs are basically milled out of a single block of steel. Because they are machined rather than cast, the tolerances can be tighter. Monoblock frogs are generally thought to create less noise and vibration than RBM frogs. Based on informal measurement that ATS performed at the PATH commuter rail system in New Jersey, it appears that the increase in noise and vibration levels with a good-condition monoblock frog is about half of that with a standard RBM frog. Flange-bearing frogs: Well-designed and maintained, flange-bearing frogs can generate much less noise and vibration than standard RBM frogs. If the ramps are too short and/or the frogs are not properly maintained, the noise and vibration benefits may be marginal. The recommended length of the ramp in the frog is a minimum of 2 feet. AREMA standards suggest a speed limit of 24 k/mi for flange-bearing frogs on transit systems, so special approval may be necessary to operate at higher speeds if a flange-bearing frog is used, One-way low-speed (OWL) frogs: OWL frogs are designed for use when traffic in the diverting direction is infrequent and low speed. Most OWL designs are flange bearing in the diverting direction and have no break in the rail in the main line direction. These are often referred to as “jump frogs” because in the diverting direction the wheels are lifted up and over the rail with some form of flange-bearing ramps. A Vossloh representative said that the cost of their OWL is about $3,000 more than a standard RBM frog and about the same as a monoblock frog. Because the rail is solid in the main line direction, there would be little or no increase in noise and vibration. Vossloh, Progress Rail and Nortrak all have variants of OWL jump frogs. Spring rail and moveable point frogs: These frogs can be substantially more expensive in terms of parts, installation and maintenance. When properly designed, installed and maintained, there can be only a marginal increase in noise and vibration levels with spring rail and moveable point frogs.


APPENDIX E. NOISE AND VIBRATION TECHNICAL REPORT

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