TheWaHJournalTM4The International Journal of Transportation-Related Environmental Noise Issues

(Ed. Note: Mr. Bendtsen reports that the RoadData Laboratory in Denmark has completeda projecton strategies fordesign andconstruc-tion ofnoise barriers. The project is based onan analysis of 40 noise barriers and noiseembankments in Denmark and Europe. In thisarticle, he details some of the considerationswhich were explored and recommendationsfor design procedures).

The bestsolution for highway noise is alwaysto lower the noise source. As regards road

traffic, this would mean that something mustbe done about the noise emission from indi-vidual vehicles. Traffic and town planningcan also be used as an effective means in thiseffort to reduce noise nuisance. This can beachieved by ensuring a sufficiently large dis-tance between residential areas which aresensitive to noise from heavily traffickedroads, as well as moving traffic from thoseroads which are closeto noise-sensitive areas.

California NoiseBarriers Task ForceReport A Summary

The basic reason behind this study was thegeneral perception that the costs of construct-ing noise barriers along State highways are toohigh. Prices to build noise barriers have beenaveraging more than ten dollars per squarefoot of wall surface. Annual maintenancecosts, where graffiti is a problem, can amountto 10% of the initial construction costs. Thesecosts are sapping resources which could oth-erwise be available for other transportationimprovements, among them safety and con-gestion relief projects.

It isCaltrans’ goal to reduce life-cycle costsand gain greater public acceptance for noisebarriers. n order to accomplish this goal, athorough study of our noise barriers policies,designs, materials, attitudes, and in particularthe latest ideas and technology in the field ofnoise barriers, wasundertaken.The basic threadwoven through the fabric of the Noise Barrierstudy was to “leave no stone unturned” in ourquest for better and/or less expensive ap-

(See California, page 7)

FHWA Mobile Noise LabIs Available for UseBy Gregg Fleming and Edward Rickley,

US DOTA’olpe National Transportation Systems Center

~n1986, the Federal Highway Administration (FHWA)initiated the National Pooled Fund Study, “Evaluation ofPerformance of Experimental Highway Noise Barriers.”The six-year study, conducted by the Noise Measure-ment and Assessment Facility (NMAF) at the John A.Volpe National Transportation Systems Center in Cam-bridge, Massachusetts, with funding support from 17state transportation agencies, is nearing a close. Amongthe many residual benefits of the study is the FHWA’smobile highway noise measurement and analysis labo-ratory which was developed by the NMAF.The intent ofthis article is to briefly describe the components andcapabilities of the mobile laboratory in the interest ofstimulating potential users.

Laboratory HardwareThe acoustic data from up to eight General Radio

Model 1962/9610 microphones and companion CetecIvie Model IE3P preamplifiers, which can be deployedin the field, are fed through several hundred feet of cable

Highway Traffic Noise in Denmark:Noise Barrier Design ConsiderationsBy Hans Bendtsen, Road Data Laboratory

A three-meter high transparent glass noise barrier in Soborg Hovedgade in Gladsaxe, Denmark.

(See Denmark, page 8)

The Federal Highway Administrations’s mobile highway noise measurement andanalysis laboratory is entirely self-contained and capable of making noise level“spot-checks” as well as extensive highway noise research studies.

(See Mobile, page 5)

The Intn,nat,onat Journal of Transportation Related Envi,onm,ntal Nose Issues

Volume One, Number 4December/January, 1992-93

In This Issue:

~ Highway Trafic Noise in Denmark .... 1

~ California Noise Barriers 1

~ FHWA Mobile Noise Lab 1

~ Editor’s Corner 2

~ FHWA Update 3

~ Al F04 Committee 4

~ Summary of Professional Papers 6

~ The Product Approval Process 10

Coming ~ssues:

~ The 1993 Caltrans SILENT” Challenge...A Design Competition for InnovativeConcepts for Abatement of Transportation-Related Environmental Noise

~ “Big Blue”... The Story of PennDOT’s 22

Miles of Noise Barriers on 1-476, the “BlueRoute”

The Wall Journal is published ten times ayear. Issues aredistributed monthly,withcom-bined issues for july/August and December/January.

The Wall journal is a publication ofAcoustiCom Publishing Corporation. Edito-rial, suhscriptinn and advertising offices arelocated at 3011 Voyage Drive, Stafford, Vir-ginia 22554. Telephone (703) 720-0282, FAX(703) 720-0598.

Publication offices are located at 617FrederickStreetS.W., Vienna, Virginia 221 80.Telephone (703)938-6745, FAX (703) 9385621.

EditorEl Angove

Director of PublicationsJohn G. Piper

About Our Dehveries.As you may have surmised

from the somewhat erratic de-liveryof our last two issues, wehave had some problems get-tingourshowonthe road. Weare new in the publishing busi-

ness, and have experienced some unantici-pated scheduling difficulties. First, our entireshipment of the September issue to our Cana-dian readers disappeared. The lastwe saw ofit was when we delivered it to the Stafford,Virginia postoffice with the required first-classpostage affixed. To remedy this unexplainedproblem, we included copies of the Septem-ber issue in our Canadian mailing of theOctober issue (a spot check with some of ourfriends in Canada indicates that the mail wentthrough).

Second, the addressed mailing labels forour October issue were apparently lost by thecourier used by our label supplier. After afruitless search for overaweek, we purchaseda label-addressing machine and now haveinternal control of that function. There werenumerous other glitches we encounteredwhich I will not describe here. It is sufficientto say that we believe we have plugged theleaks and that the mailing of this combinedissue will permit us to get back on a regular

Requestfor Information

James P. Cowan is under contractwith VanNostrand Reinhold, the New York City-basedpublishing company, to write a book entitledHandbook of Environmental Acoustics, to bepublished toward the end of 1993. The bookwill be a basic reference in all areas ofenviron-mental noise pollution for people with little orno knowledge in the field. Anyone whowouldlike to submit data (particularly noise levelmeasurements which show the effectivenessof noise barriers in the mitigation of highwaytraffic noise) or interesting field experiences,to be included in the book, is welcome to doso. A letter of permission to use the informa-tion in the book must accompany all submis-sions. All material used in the book will bereferenced to the appropriate authors. Sub-missions must be received by January 15,1993 to be considered for inclusion in thebook. Submissions should be sent to:

James P. CowanCowan & Associates, Inc.1 Opal CourtNewtown, PA 18940-2435Telephone: (215) 579-9050

monthly mailing schedule. Thanks for yourforbearance in this matter.

About Our New Format.Some of our problems were caused by our

110 x 14” tabloid format. Although we think itlooks great, our printer has a loaded scheduleon the particular press needed to run this size.A magazine size, 8 1/2” x 11”, is much easierfor them to run on a number of presses, andwill speed delivery. Also, we had commentsfrom a number of readers that their issuearrived in abattered condition. The postofficeassures us that the magazine size will faremuch better in the mail sorting and handlingprocesses.

It also allows us to go back to two-colorissues as a standard, and the possibility ofsomefour-color pages. Wehopethatyou likethis format. We will be adding more photosand graphics and different layouts to promotegreater reader interest.

What We Need Now~.Is greater readerpartkipat~on.Wecannot

invent material to print. We must have yourtechnical articles, news of noise programs,research and development activities, projectsin progress, field experiences and new con-cepts. Please help.

New ProductAnnouncementThe SILATOR

A Small Volume ResonatorA new resonator element , called a

SILATOR, has been designed for use asa noisecontrol device. A SILATOR consists of anevacuated lentiform convexcap ofsheetmetal.The effect of a SILATOR is comparable to thatof a Helmholtz resonator. Broad-band noisecontrol may be achieved by tuning a set ofSILATORs to different frequencies.

Helmholtz resonators are effective only ina relatively narrow frequency range centeredaround their resonantfrequency, and are therefore used for suppressing discretefrequencies. Despite the physical advantageand technical ruggednessofa Helmholtz reso-nator, it is impractical to be used for attenuat-ing broad-band noise because of the requiredinstallation volume. Reducing the stiffnesscomponent of the acoustic impedance re-quires a large resonator volume.

This constraint also limits the low fre-quency performance of the foil sound ab-sorber described by Mechel and Kiesewetter.These foil absorbers consist of sealed plasticcaps. The enclosed air acts as a spring, while

see Silator, page 9

TheWall Journal I Editors Corner

Submissions of papers, articles, letters,and photographs for publication, as well asrequests for our advertising rate scheduleshould be addressed to The Wall Journal,P.O. Box 1286, Stafford, VA 22555-1286.

All materials become the property of theWall Journal, and may be edited for length,clarity, and accuracy. Materials will not bereturned without special arrangements priorto submission. The Wall Journal cannot beresponsible for lost or damaged materials.

2

FHWA Update by Bob Armstrong

Highway TrafficNoise Analysis Training

The Federal Highway Ad-ministration (FHWA) contin-ues to offer a 32-hour Na-tional Highway Institutetrain-ing course entitled “Funda-mentals and Abatement ofHighway Traffic Noise”. The

course is taught by FHWA staff and focusesheavily on FHWA noise policies. It is pre-sented at the request of a host State highwayagency (SHA) and is directed primarily toFHWA and SHA personnel who have respon-sibility for implementing FHWA’s noise stan-dards through the identification, analysis andmitigation of highway traffic noise impacts.The hostSHA may invite local agency staff andprivate consultants to attend courses if space isavailable.

Two other known sources provide high-waytraffic noisetrainingwhichfocuses heavilyon technical noise analysis. These trainingsessions are approximately a week in lengthand have a registration fee of $795 - $850,which includes an extensive setof microcom-putertraffic noise analysis software (STAMINA2.0/OPTIMA plus more). These sources are asfollows:

Highway Noise Analysis SeminarUniversity of LouisvilleTelephone: 502 588-6456

Advanced Traffic Noise ModelingVanderbilt UniversityTelephone: 615 327-8130

MicrocomputerVersions ofSTAMINA2.O/OPTIMA. FHWA receives numerous requestsfor microcomputer versions of STAMINA 2.0/OPTIMA. Since FHWA has never developedsuch microcomputer software, we refer in-quiries to the following known marketingsources:

Mr. Alex VeressTowne, Richards & Chaudiere, Inc.105 N.E. 56th StreetSeattle, Washington 98105Tel: 206 523-3350

Ms. Shirley LakeTrinity ConsultantsSuite 120012801 N. Central ExpresswayDallas, Texas 75243Tel: 214 661-8100

Dr. William BowlbyBowlby & Associates, Inc.6403 Waterford DriveBrentwood, Tennessee 37027

Dr. Louis Cohn or Dr. Al HarrisUniversity of LouisvilleDepartment of Civil Engineering

Louisville, Kentucky 40292Tel: 502 588-6276

Highway Traffic Noise Research. The fol-lowing information on highway traffic noiseresearch has recently been compiled for theNationally Coordinated Program of HighwayResearch, Development and Technology forthe year ending September 30, 1992:

Significant ResultsDuring the Past Year• “Determination of Traffic Noise Barrier Ef-

fectiveness: An Evaluation of Noise Abate-ment Measures Used on 1-440” evaluatedthe reduction in traffic noise levels due todepressing the highway and the added ef-fectiveness of both reflective and absorptivenoise barriers constructed along the high-way (Tennessee DOT).“Parallel Barrier Effectiveness Under Free-Flowing Traffic Conditions: evaluated thedegradation in acoustic performance of ahighwaytraffic noisebarrierduetothecloseproximity of a parallel barrier on the oppo-site side of the roadway (FHWA PooledFund study).

• “Extension of Reference Emission Factorsforthe STAMINA 2.0 Model to include 55-65 MPH” determined highway traffic noisereference energy mean emission levels fortraffic speeds of 55-65 mph on selectedopen, flat sites along major heavily-trav-elled Florida highways (Florida DOT).

Work Underway“Improving Highway Traffic Noise Predic-tion Procedures” has been improving high-way traffic noise prediction procedures byreevaluating the reference energy meanemission levels and incorporating recentadvances in traffic noise acousticsand com-puter technology. Phase 1 is producing anextensive literature review and resultingrecommendations for improved procedures(FHWA).

• “Traffic Noise Attenuation as a Function ofGround and Vegetation” has been evaluat-ing decreases of traffic noise levels withdistance from highways due to variousground conditions (California DOT).

• “Determination of Truck Noise Levels forNew jersey” has been determining refer-ence energymean emission levelsfor heavytrucks on highway upgrades in New jerseyand has been developing a simple methodfor predicting the noise due to heavy truckson highway upgrades (New Jersey DOT).

• “Evaluation of Innovative Noise Barriers”has been evaluating the effectiveness oftwoconcrete post-and-panel highway trafficnoise barriers. One barrier was tilted tendegrees away from the roadway; the otherbarrier was covered with a proprietary ab-sorbing finish (NewJersey DOT).

• “Multi-Level Roadway Noise Abatement”

has been evaluating the problem of trafficnoise impacts from a multi-level viaductand the potential of addressing the problemwith the addition of acoustically absorbentmaterial on the underside of the upperdeckof the viaduct and the construction of trafficnoise barriers on both sides of the lower andupper decks of the viaduct (WashingtonState DOT).“The Effectof Roadway Wearon Tire Noise”has been examining how vehicle tire noisechanges with time as pavement ages andwears. Forty- one pavement sections arebeing studied biannually for a ten-year pe-riod; the sections include both asphalticand concrete compositions (WashingtonState DOT).

• “Special Noise Barrier Applications” hasbeen examining the technical and eco-nomic feasibility of special applications ofhighway traffic noise barriers, includingabsorptive barriers (both single and paral-lel), fully slanted barriers, barriers withslanted tops, T-top barriers, and barrierswith dispersive faces and roughened tex-tures (Washington State DOT).“Noise Mitigation Strategies” (WA HP&R)has been (1) reassessing feasible and cost-effective noise-reduction strategies foreachnoise-producing component of motor ve-hicles; (2) updating the estimates of thenoise abatement potential and associatedcosts for motor vehicles; (3) reviewing thesuccess of federal, state and local laws andordinances for vehicle noise control; (4)evaluating the success of community mea-sures to reduce the impactof highwaytrafficnoise, including land-use strategies, zoningregulations and building design standards,and retrofit sound-insulationtreatments; and(5) developing system-level noise abate-ment strategies, comparing the costs andbenefits of reducing noise at the source,along the path, and at the receiver (Wash-ington State DOT).“Update of Truck Noise Levels in Newjersey” has been developing new energymean emission levelsfor medium and heavytrucks operating in New Jersey (NewJerseyDOT).“Evaluation of Performance of Experimen-tal HighwayNoise Barriers” has been evalu-ating different noise barrier designs and theseparation-distance to barrier-height ratioof parallel noise barriers (FHWA Pooled-Fund Study).“Design of Noise Barriers Using ArtificialIntelligence” has been developing an artifi-cial intelligence design procedure for high-way traffic noise barriers (California DOT).

• “Specialized Noise Barriers for Use onBridges” has been evaluating alternatives toinclude retrofit noise barriers on bridges,including better bridge supports and meansto relieve wind loads (New jersey DOT).

see Update, page 9

TRB AIFO4 Committee by Domenick Billera, Chairman

Notice for 1993 Winter Meeting

TheWinter Meeting of the TRB Al F04 Com-mittee on Transportation-Related Noise and

Vibration will be conducted atthe Transportation ResearchBoardAnnual MeetingonJanu-ary 10-14, 1993 in Washing-ton, D.C. Details and scheduleswillbe announced bytheTrans-portation Research Board. Fol-lowing is the agenda for the

Al F04 Committee activities. The professionalpapers and presentations have been dividedinto two-part Super-Sessions.

Session 176A - 1/13193 8:30 AM“Type U Noise Abatement - Programs, Policies and Pri-orities”Presiding: Kenneth PolcakMaryland’s Type! Noise Abatement ProgramKen Polcak (Maryland State Highway Administration)Type II Program Priority System Development for WisconsinDOTJohn R. Jaeckel (Howard, Needles, Tammen and Bergendoff)Type II Noise Abatement: The New Jersey ExperienceDomenick Billera (New Jersey Department of Transportation)Type!! Noise Abatement Study for the New JerseyTurnpikeBela Schmidt(Louis Borger and Associates, Inc.)Barrier Priority Program forthe Massachusetts Turnpikechristopher Menge (Harris Miller Miller and Hanson)Session 176B - 1/13/93 - 10:30 AM“Evaluating the Noise Reduction Provided by Sound~nsuIation

Modifications in Homes Near Commercial Airports”Presiding: Eric Stusnick (Wyle Laboratories)Results ofThe Residential Sound Insulation Program atLogan AirportCarl Rosenberg and Frank lacovino (Acentech, Inc.)Use ofa Synthesized Aircraft Noise Source forMeasurementsof Outdoorto IndoorNoise Reduction in a Reno ResidentialDevelopmentRobert Brown and Jim Buntin (Brown-Buntin Associates, Inc.)

Comparison ofTechniques for Evaluating Sound InsulationDana Hougland and Michael Barnhardt (David L. Adams As~sociates, Inc.)User-Friendly Sound Insulation ProgramsAndrew Harris (Harris Miller Miller and Hanson, Inc.)The Use of Aircraft and Artificial Noise Sources in the Mea-surement of Residential Noise ReductionBen Sharp, Vijay Desal and Kevin Bradley (Wyle Laborato-ries)Session 201A - 1/13/93- 2:30 PM“Highway Noise: Emission Levels and Abatement”Presiding: David R, StillDevelopment of Reference Energy Mean Emission Levels forHighway Traffic Noise in FloridaRoger Wayson, of a!

Reference Energy Mean Emission Levels for Riyadh, SaudiArabiaParviz Koushki, of a!

Special Noise Barrier ApplicationsLouis F, Cohn, of al

Determination of Traffic Noise Barrier Effectiveness: An Evalu-ation of Noise Abatement Measured on -440Lloyd Herman, of al

Session 201B-Ill 3/93 - 4:00 PM“Rail Transportation Noise and Vibration”Presiding: Carl HansonSound-Absorptive Fence for Light Rail Transit in the City ofCalgaryU. Gandhi, et alThe Effect of Rail Straightness on Wayside Ground VibrationJames Nelson

Radiated Aerodynamic Noise Generated by High SpeedTracked VehiclesDr. W. F. King Ill (Federal Republic of Germany)Wayside Noise Generated by the German High Speed TransitSystems ICE and TransrapidDipl.-Ing Bernd Barsikow (Federal Republic of Germany)

The Al F04 Committee business meetings are all scheduledon the previous day, January 12, as follows:2:00 PM - Aircraft Subcommittee MeetingHighway Subcommittee MeetingRail Subcommittee Meeting

7:30 PM - Full Al F04 Committee Meeting

The Annual Committee Awards Dinneris set for Wednesday evening, January 13.This looks to be the Biggest and Best Al F04winter meeting in recent years. Don’t miss it!

Domenick Billera may be contacted atNew Jersey Department of Transportation,telephone: 609 530-2834or fax 609 530-3893.

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Mobile, from page 1

to the data processing system inside themobile laboratory. Raw data processingand storage is accomplished by eightportable Cetec Ivie !E-30A one-tb ird-oc-tave spectrum analyzers, interfaced withan on-board IBM PC-AT microcomputer.

Two analog outputs from the analyz-ers, the one-third -octave band level out-put and the sound level meter (SLM)output, are fed directly to the analoginput of a Data Translations DT2821-l6-SE analog-to-digital (ND)converterboardinside the PC. A third analog output, thesawtooth timing signal, is connected to aspecial interface card which converts thesawtooth signal into two TTL-compatiblesignals, a trigger signal and a timing sig-nal. The converted trigger and timingsignals are then connected to the 16digital I/O ports on the ND board.

During data collection, the A/D boardin conjunction with the PC are pro-grammed to sample, digitize and store inPC memorythe 32 one-third-octave bandlevels using the associated trigger andtiming pulses, as appropriate. After sam-p1 ingthe 32 one-third-octave band levelsfor each analyzer, the SLM signal level,which requires no timing alignment, isalso sampled, digitized and stored.Laboratory Software

All system functions are controlled bytwo NMAF-developed computer pro-grams: a data collection program(HWINPUT) and a data processing pro-gram (HWNOISE). The HWINPUT pro-gram is used to collectacoustic data fromup to eight analyzers in averaging timesas short as one-eighth of a second for upto 120 individual measurements. Aver-aging times and measurement periodsare user-defined and controlled byaclockboard which is internal to the PC. Afterdata collection is complete, the PC auto-matical ly downloads the raw data to afileon a user-selected disk drive. Reductionand processing of the raw data files isperformed usingthecompanion program,HWNOISE.

The HWNOISE processing programautomatically applies calibration adjust-ments to the raw data and uses thesedatato calculate various noise level indices,includingtheequivalentsound level (LeQ)and the sound exposure level (SEL) forindividual measurement events. Thesedata can then be displayed in varioustabular and graphical formats. Detaileduser’s guides for both HWINPUT andHWNOISE have been prepared and areavailable to interested individuals.AdditionalLaboratory Accessories

In add ition, the mobile laboratory con-tains all pertinent support accessoriesneeded to perform advanced highwaynoise research. They include: aClimatronics Model EWS weather

station,capable of measuring and record-ing temperature, humidity, wind speedand wind direction; four portable mea-surement masts which can be set forheights up to 30 feet above the ground;calibrators, pink noise generators andmicrophone simulators; 10 reels of mi-crophone cable, each 500 feet in length;and spare microphones, analyzers andpreamplifiers.

Additional instrumentation which maybe needed, depending on requirements,would include a doppler radar gun formeasuring vehicle speeds, and a moreadvanced meteorological system capableof both downloading data directly to thePC and measuring meteorological condi-tions at multiple heights.Summary

The FHWA’s mobile highway noisemeasurement and analysis laboratory is

entirely self-contained and capable ofboth quick “spot-checks” of noise levels,as well as extensive highway noise re-search studies. In addition to the thou-sands of hours of rigorous use the systemexperienced during the Pooled FundStudy, it has since been successfully usedfor highway noise studies by the Univer-sity of Central Florida and by the Mary-land State H ighway Adm inistration. It is avaluable resource which is available tointerested state transportation agenciesfor both in-house research as well asstate-sponsored research.

For additional information, contactGregg Fleming at (617) 494-2372. Indi-viduals interested in using the system forhighway noise studies should contactRobert Armstrong of FHWA at (202)366-2078.

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D

Siuiimary of ProfessionalPapersPresented at the TRB Al F04 Summer Meeting at Milwaukee: July 21-24, 1991 - Part 1

These summaries are the second in a con-tinuing series which will provide a chronicleof all the professional papers presented atA 1 F04 winter and summer meetings, begin-ningin 1978.

The fol lowing, printed in order ofpresenta-tion, are summaries of the papers presented atthe 1991 summer meeting of the TRB Al F04Committee on transportation noise and vibra-tion.

Co ees eS wae aHg a ose a ss

by Al Harris and Louis CohnPresented by: Dr. Al HarrisUniversity of LouisvilleDepartment of Civil EngineeringLouisville, KY 40292(502) 588-6276Summary: The development of comput-

erized noise prediction and barrier designtools can be traced back to 1963. Throughresearch funding efforts atthe national level,improved prediction methodologies and mod-els have subsequently evolved. Since thefirst research, various algorithms were de-veloped and revised which were incorpo-rated into SNAP 1.0, the first FHWA comput-erized model fortraffic noise prediction. Laterrevisions led to STAMINA 1.0 and later, theBarrier Cost Reduction (BCR) procedure.

Along with advancements in highwaynoise analysis methods, various pieces ofsoftware have been developed to handlespecific, but separate, issues associatedwith complex problems. While being devel-oped to address specific tasks, there havebeen only lifnited efforts to integrate theseseparate packages into a single compre-hensive library. As a result, the noise analystis required to manually compile and executedata files while managing the location of allthe data input and program output.

With the widespread availability of mi-crocomputers and associated software, asignificant problem has emerged relative tothe varying skill levels of various users. Inorder to effectively and efficiently accom-plish this complex task, the user must bevery familiar with the operation of the com-puter, as well as the process of developinginput data, generating output, and manag-ing the location of both input andoutput files.

This presentation describes a powerful,flexible, but easy to use prototype systemwhich is capable of managing analysis pro-grams, as well as the location of input/outputfiles. This system also provides a mecha-nismfor electronicallyconstructing inputfilesas well as a plofting routine for checkinginput data and generating hardcopy plots.

Other programs, in addition to STAMINA2.0/ OPTIMA, are also available in the sys-tem for construction noise analysis, multiplereflections analysis from parallel walls, anda prototype expert system for automatednoise barrier design.

C~r~-~PJ’,,F~I’cseMa~o:-~9r’~TP:‘mis

‘i (‘~ci1I(’(I I 0 : Ri ~hvrll\i ui.iCirrus Research, Inc.6818 W. State Street, Suite 170Wauwatosa, WI 53213(414) 258- 0717

Summary: This is a discussion of the noisemonitoring terminals used to make a noisemap of England. lnl 989, the United KingdomDepartment of the Environment issued aninvitation for companies to tenderfor a newNational Noise Survey. The survey was tomeasurethe noise climate at 1,000 sites acrossEngland and Wales over a 24-hour period.Each 24-hour period was to be during week-days only. Measurements were to be made inreasonable weather conditions. The measure-ments required were to be LA1, LAb, LAO, LAYO,LAA, and LA, foreach hourduringthe 24-hourperiod. The ~RL702 Logging Integrating SoundLevel Meter in a waterproof case equippedwith an outdoor microphone was used for thesurvey. In addition to the required measure-ments, hourly Peak, LA,,,,, LA and 2-secondshort L,q levels were acquired. Each day, 10unitswere placed at 10 selected locations. Thenext day, data from each unit was down-loaded into a TOSHIBA Tl000 battery com-puter in the car. If the data was unusual, 2-second short LA,. levels for the 24-hour periodwere also down?oaded to analyze the data indetail. The 10 units were then transferred tothe next 10 sites. Using this method, the staffatAlRO Ltd. Hemel Hempstead HertfordshireU.K. were able to analyze the environmentalnoise throughout an entire country.

N~ise Ana~ys~sfo- proposed i-i&isteo- Shadys~de:lospital (P:ttsb rgl-’, PA)

Fr(,c’iil((I by: l~d\’id(‘nalt’Acentech Incorporated125 Cambridge Park DriveCambridge, MA 02140(61 7) 499-8019Summary: Shadyside Hospital has applied

for a permit to construct an emergency medi-cal-use helicopter landing facility on the hos-pital roof. This paper addresses the potentialcommunity noise impact of helicopter opera-tions for the proposed facility.

The study consists of I) ambient noisemeasurements in thevicinity ofthe hospital; 2)computer projections of helicopter noise 1ev-

els usingthe Federal Aviation Administration’sHeliport Noise Model; 3) actual measure-ments of helicopter noise at a site comparableto Shadyside Hospital; 4) comparison of pro-jected helicopter noise with relevant regulat-ing criteria and existing ambient noise levels;and 5) measurement and analysis of hospitalfacade sound reflections.

Existing ambient noise levels influence theacceptability ofthe projected helicopter noiselevels. Under the City of Pittsburgh HelicopterRegulations, ambientnoise levels are nottakeninto consideration until the day-night level(LA,) reaches 75dB. Ambient noise levels weremeasured for 40 continuous hours at 5 loca-tions near the hospital. A-weighted LA,, valuesranged from 55 to 72 dB. The 72 dBA valuewas measured near the end of Colonial Placeand ranged from 55 to 72 dB. The 72 dBAvalue was measured near the end of ColonialPlace and was caused primarilyhyfreighttrainactivity in the area. During the course of 24hours, 52 freight trains, 1,107 buses, 44 air-craft, and 13 helicopters were observed topass by this location. Using federal noisecriteria (ANSI, FAA, HUD), this areawould beconsidered incompatible for residential use,irrespective of the proposed landing facility.

Helicopter noise levels were projectedusing FAA’s Heliport Noise Model (H NM) asrequired by the FAA and the Pittsburgh Heli-copterLanding FacilityOrdinance. The modelprojects noise contours around the site for thepurpose of evaluating compatible land useswithin various noise contours. This analysisindicated that day-night noise levels in thecommunity due only to helicopter operationswould range from 40 to 53 dBA.

To supplement and verify the HNM re-su Its, noise measurements ofactual helicopteroperations were also made. Since helicopterscannot currently land on Shadyside Hospital,and since takeoff and landing operations playa major role in the noise generation, an exist-ing helistop at Westmoreland Hospital(Greensburg, PA) with comparable geometryto Shadyside was used for the noise measure-ments. The noise measurements forthis analy-sis were in close agreement (within 1 decibel)with results of the FAA Heliport Noise Model.This is significant since the computer-gener-ated noise contours provide acomprehensivemeans of evaluating the potential noise im-pacts at all locations surrounding the pro-posed helistop.

Helicopter operations are projected toproduce a day-night level of 53 dBA at theclosest residence. This is welI-belowthe ANSI,FAA, and HUD criteria of65 dB Ld,.for residen-tial use. Helicopter noise levels will also bewell-below the Pittsburgh noise ordinance of75 dB Ldn. Additionally, the noise levels due

see 1991 Papers, page 12

6

California, from page 1

proachesto providing noise attenuation alongCalifornia’s freeways.

The study was performed by a Task Forcemade up of Caltrans engineers and architectsrepresenting project development, structuresdesign and architecture, landscape architec-ture, materials and research, and value engi-neering, from both Headquarters and the Dis-tricts, and included members of private indus-try representing the Precast Concrete and theConcrete Masonry Associations. In addition,information and advice was obtained from avariety ofotherCaltrans employees,wall manu-facturers and builders, Federal Highway Ad-ministration reports and articles, and fromnewspaper or magazine articles.

The History of Noise BarriersCaltrans first became interested in mitigat-

ing noise in the l950s. Early research wasaimed at controlling noise during highwayconstruction. In 1968, in response to publicconcern, Caltrans built the first noise barrierstocontrol everyday highway noise along free-ways. These first two sound walls were builtin San Francisco and near San jose. It was alsoin 1968 that Caltrans established policy andprocedures for freeway noise barriers, policythat has become more specific but not substan-tially different in intent over the years since.

The passage of both the National Environ-mental Policy Act (NEPA) in 1969 and theCalifornia Environmental Quality Act (CEQA)in 1970 required Caltrans to study and toconsider noise effects, and to mitigate thoseeffects when they could have been significant,in the building of highway projects. TheFederal Highway Administration (FHWA) in1973 adopted policy and regulations, nowknown as 23-CFR-Part-772 (formerly FHPM-7-7-3), that clearly defined when highwaynoise was considered to be high enough torequire consideration of noise mitigation.These regulations apply to any project onwhich federal funds are used.

In 1974, Caltrans established a retrofit pro-gram to build noise barriers along freewaysbuilt before the noise barrier program, butwhere noise levels were sufficiently high towarrant a noise barrier under the current poli-cies. A shortage of highway funds during theperiod from 1974 through 1976 preventedCaltrans from actually undertaking any retrofitnoise barrier projects until 1977. By that timethe Legislature, which was interested but wasseeing little progress, placed into statute arequirement for a retrofit noise barrier pro-gram, with the California Transportation Com-mission to program projects consistent withavailable funding.

It is estimatedthat Caltrans has spent about$300 million on noise barriers to date, con-structing about 330 miles of noise barriersalong oururban and suburbanfreeways. About50% of the noise barriers have been con-structed in the Los Angeles area, about 30% inthe San FranciscoBay area, and the remainder

in other urban areas scattered around the state.Since the noise barrier program became wellestablished, the cost of the program has repre-sented about 5% of the Department’s overallcapital outlay for highway improvements.

Noise Barrier CostsUp until now, the predominant material

used for noise barrier construction has beenmasonry block. Of the noise barriers con-structed to date, approximately 85% are ma-sonry block, about 10% are precast concretepanels, and the remaining 5% are of othermaterials such as metal, reinforced stucco,wood or earth berms and mounds.

Over the years, the Department has madea conscious effortto increase competition anddecrease costs by specifying the use of mate-rials other than masonry block, and the use ofdifferent construction techniques. The efforthas not been particularly successful. Forinstance, in 1991 the Department receivedbids on a precast concrete panel project util iz-ing a different and reportedly less expensivesupport system. The bid price for the precastpanel project was $10.25 per square foot.During the same period, the average bid priceofmasonryblocksoundwallswas$lO.42 persquare foot. Both prices are for sound walls tobe located near the right of way line, andinclude the wall, foundations and footings,but exclude safety shape barriers, traffic han-dling, drainage, etc.

Also during the past 1991 year, the Depart-ment received bids for a project on Route 101in Los Angeles, which specified heavy timberfor the sound wall material. The low bid pricewas $16.00 per square foot. This comparesrather unfavorably with an average bid price,during the same period, of $10.42 per squarefoot. Earlier, in 1985 the Department speci-fied a timber wall on another project, in SantaBarbara, which resulted in a bid price of$11.00 persquarefoot. Thiswouldescalatetoa present cost of about$1 5.00 per squarefoot.

The history of noise barriers in Californiadoes not lack in examples such as those notedabove. More often than not, when alternativesto masonry block are specified, such alterna-tives are bid higher than normal block walls.Often, when the other materials are dictated,to insure that they are in fact constructed, thelow bids come in higher than the usual ma-sonry prices.

Framed plywood wallswere recently con-structed along Route 85 in Sunnyvale, under aMeasure funded project, for about $10.00per square foot. Since the first of this 1992year, bid prices for masonry block soundwalls (constructed ator nearthe rightof wayline) have ranged from $8.85 to $13.00 persquare foot, with a median price of $1 1 .02per square foot. This is the cost only of thesound wall and footings, but does not in-clude other associated costs such as clear-ing and grubbing, drainage, or landscapemodifications.

Caltrans Action ProgramRecomniended by the Task Force1. Establish new design guidelines for noise

barriers that stress simplicity.2. Use plantings more freely as elements of

noise abatement features to allow simplerbarriers and to deter graffiti.

3. Reviewcurrentstructural design criteriaforopportunities to obtain cost savings by de-veloping more economical designs.

4. Develop a standardized column/post/foot-ing support system to accommodate a vari-ety of panel-type materials.

5. Establish a review group to evaluate newproducts from vendors that can be used fornoise barriers, and develop a package ofevaluation criteria and design standards forvendors.

6. Invite private companies to construct testsections of noise barriers, using their newconstruction and materials concepts to re-duce capital and maintenance costs.

7. Use demonstration projects to evaluatethose new noise barrier concepts whichshow promise, but have not yet been built inCalifornia.

8. Obtain industry ideas on lowering the costof building noise barriers, and adopt thosewhich are reasonable and practical.

9. Use life-cycle costs in the process ofselecting the noise barrier solution.

10. Resolve the question as to whether con-struction of noise barriers increases reflectednoise on the opposite side of the freeway.

11. Organize a contest among students inter-ested in noise barriers as an endeavor tomake use of the variety of talent that isavailable in California colleges and univer-sities.

12. Issue instructions to Caltrans’ designers toactively develop innovative noise barrierdesignswhich incorporate salvaged materi-als, particularly highway hardware materi-als.

13. Study the concept of offering contractorsa design/build process for noise barrierprojects.

Ed. Note: The above are excerpted from thecomplete 85-page Task Force Report, whichcontains Sections on: Requirements of theStatutes/Policy/Programs; Fundamentals ofNoise and Noise Barriers; Design Criteria;Aesthetic Considerations; ApprovedCa/trans Design Alternatives; Design, Con-struction and Bidding Processes; CostAnalysis; New Concepts; and the ActionProgram. For further information on the re-port, contact Robert Vogel at:

California Department of Transportation,Sacramento,telephone: 916 654-2477fax: 916 654-3770.

7

Denmark, from page 1

Noise Barriers.In areas where it is

not possible within ashort foreseeable pe-riod of time to reducenoise nuisance byplanning action, itmay be necessary to

establish noise barriersor noise embank-ments. Unfortunately, these arefrequentlylarge and characteristic constructions,which can contribute considerably toleaving their mark on the road and com-munity environment in which they aresituated.

Starting Point for Design.Seen from an aesthetic point of view,

noise barriers will most frequently beunwanted. The visual environment willdeteriorate, seen both from the road andthe community. Therefore, it is importantnot only to reduce the environmentalnoise nuisance from the road but also totake into account the appearance andcharacter of the surrounding area. Thedesign ofthe noise barriers mustbe basedon the area surrounding the road and thefunction and design ofthe area as well asthe amount of traffic and its speed.

Speed of Traffic.The noise barrier construction is

viewed by various traffic user groupspassingtheconstruction atvaryingspeeds.

Residents living near the noise barrierhave a direct and continuous view of itfrom their windows and open spaces.Pedestrians and cyclists pass the con-struction at low speed and are thereforeable to note details and variations in thebarrier shape and choice of color.

Drivers, passing the construction atlow speed (30-50 km/h) are able to notethe larger details. Drivers, passing at aspeed of 80-100 km/h) are, however,only able to note general elements ofdesign as shapes with different contrastsand colors.

Town and Country.In areas of urban estates a greatdeal of

thought should be given to make thenoise barriers fit in with the type of con-structions around them, since it is herethat the local population has to live withthese barriers and also since it is in urbanareas that the road users moving at walk-ing or cycling speed will note the detailsof the barriers.

The barriers should under all circum-stances have two ‘front sides’; one whichfaces the roadway and one which facesthe surrounding areas. The acoustic de-mand for noise reduction must not be theonly decisive factor for the height andshape of the barrier, since visual criteriacan also be of importance for the choiceof height.

Evaluation of the Local Inhabitants.Investigations conducted in the Nether-lands show that inhabitants behind anoise barrier very soon forget the formerhigh noise levels and thereafter becomedissatisfied with lost or reduced view, ifthe noise barrier has been constructedtoo close to their homes. This is a nui-sancethatthe inhabitants will have to livewith every day for many years.

Visual Impact.Noise barriers can appear, dueto their

height, as dominating constructions. Thefollowing means can be used to reducethe visual effect of a high noise barrier:• Use of colors, in which the barrier

is constructed with horizontalcolor bars, having light colors onthe upper courses and dark colorson the lower courses.

• Use of transparent panel materials.• Constructing the barrier at a slight

angle away from the road.• Use of low plants in front of the

barrier and high plants behind thebarrier.The higher a noise barrier construc-

tion is and the closer it is to the road or aresidential area, the more effective is thenoise protection. On the other hand, theinfluence on the surrounding area andthe road environment is more dominant.

The Planning Process.In the connection with the

process where a noise barrierconstruction is planned anddesigned, it is important toconsiderthe wishes and pointsof viewof those people livingin the area. It is important toensure thata noise problem issolved, while a new visualproblem is not created.

Furthermore, it is impor-tant to include the authoritiesand organizationswhich havean interest in the project insome way. This could betraffic safety people, archi-tects, landscapearchitects/de-signers and road planners.

Other European DesignStrategies.

In European countries,various points of view andprinciples for the choice ofnoise barrier construction areused. Some of these follow:~ Cologne. Primarily a wishto make the construction fitinto the area as a part of na-tu re, based on the recognitionthat these constructions are aforeign element in the coun-tryside and in towns.~ Hannover. Noise barriersare constructed asa landmark.

THE SOUNDTRAP® ENVIRONMENTAL BARRIERAdvancingTheStandards

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8

Silator, from page 2 Update, from page 3

Use of industry-designed barriers with marked,individual variations.~ Holland. Variation and adjustment to thesurroundings, seen from the understandingthatwhen noise barriers and/or embankmentsare to be constructed, they may be equallywell-used to create variation and possibilitiesof aesthetic interest alongside the road and itsenvironment.~ Paris. Not in favor of industry-designedconstructions without direct adjustment to theurban environment. The result is that manynoise barriers around Paris are independent,sculptural additions to the local environment.

The report, “Noise Barriers-An IdeaCatalog”,may be ordered from UI Ia Hansen atthe RoadData Laboratory, Road Directorate, DanishRoad Institute, Stationsalléen 42, P.O. Box 40,DK-2730 Herlev, Denmark (fax +45 42 91 6141).The price is 355 DKK. The report is illustratedwith many color photographs. Aten-minute videotape is available at a price of500 DKK.

the walls act as very thin plates exhibitingbending resonances at low frequencies. Themany bending resonancies of the thin plasticwalls allow a relatively efficient coupling be-tween the acoustic field and the vibrationresponse of the walls. Sound absorption isachieved by the dissipation of the vibrationenergy in the thin plates. Asfar as the requiredinstallation volume isconcerned, this acousticabsorber offers little advantage over theHelmholtz resonator.

Another device of this group, which func-tions by interactingwith the acoustic pressure,is the SILATOR or vacuum bubble resonatorsuggested by Bschorr. In this device, lens-shaped capsule walls enclose an evacuatedspace. The capsule volume may be made assmall as desired since, because ofthe vacuuminside, there is no airstiffness. This device alsoembodies a resonator, which is formed by themass and stiffness of the walls.

The object of the study reported in thispaper is to establish the principles of thisresonator technology and to yield technicalinformation needed for designing these reso-nator elements for various applications.

To obtain a copy of the complete report,please contact Richard Sohn at:

PCVTechnologiesP.O. Box 84Niceville, Florida 32588-0084.

• “Public Response to Noise Barriers” hasbeen evaluating methods for determiningpublic responses to highway traffic noiseand noise barriers. The study includes (1)designing an appropriate questionnaire, (2)conducting a survey, (3) analyzing the re-sults, and (4) developing conclusions andrecommendations (NewJersey DOT).

• “Normalizing Traffic Noise Measurementsfor the Effects of Meteorology” has beendeveloping a procedure for making adjust-ments to highway traffic noise measure-ments for wind direction and wind speedsupto 12 mph (19.3 kph) (California DOT).

PLANS FOR NEXT YEAR• “Improving Highway Traffic Noise Predic-

tion Procedures” will improve highway traf-fic noise prediction procedures by reevalu-ating the reference energy mean emissionlevels and incorporating recent advances intraffic noise acoustics and computer tech-nology. Phase 2 will involve the develop-ment of new computer software for trafficnoise prediction (FHWA).

Questions and comments concerning thiscolumn should be directed to Bob Armstrongat 202 366-2073 or Steve Ronning at 202 366-2078.

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9

The Product Approval Processby Soren Pedersen

Part H - Preparing the Submission

fhe presentation of thenoise barrier design

submission for acceptanceby a transportation agencyis the most critical stage ingetting a noise barrier prod-uct approved and must

neverbe treated lightly. It can also be the mostfrustrating for both the manufacturer and theapproving agency. The key is in knowingwhat the requirements and specifications arefor acceptance by the agency. And, just asimportant, in what formatthe agency is accus-tomed to reviewing such submissions.

Since highway and transportation agen-cies are dealing with public funds, they areobligatedto ensure thatevery productused ona roadway meets durability, safety and func-tionality requirements, as well as being costeffective. How this is accomplished variessignificantly among agencies. Many haveadopted to some degree the approval strategyand principles outlined in the National Coop-erative Highway Research Program, Synthesisof Highway Practice, Report 90: New ProductEvaluation Procedures.

Although this report details the proceduresfor the evaluation of new or unusual products,designs and concepts, it is equally relevant for

common products such as noise barriers froma new or existing manufacturer. Even thoughthis report was written over ten years ago, theinformation contained in it has withstood thetest of time and will do so for years to come.

It is critical that the submission packagepresented is complete. Every aspect of theagency requirements must be thoroughly ad-dressed. Otherwise, the response time for anincomplete submission may be just as long asfor one which has gone through the entireevaluation process. And at the end of it, theonly response could be avery brief notestatingthat the submission in its present form wasincomplete and to please try again.

To avoid this type of rejection, first contactthe approving agency to learn what the specific requirements for acceptance are. litherequirements reference local agency specifi-cations, find out howto obtain the latest copyof these. This is true for both first time appli-cants and repeats. If parts of therequirementsare unclear, do not hesitate to ask for moredetails or a clarification before proceeding. Ifspecific requirements are not available orhave notbeen developed by the agency, thenthe basic acceptance principles of durability,safety, functionality and costeffectiveness mustbe thoroughly addressed and proven.

The current trend in writing specificationsis leaning toward performance-oriented re-quirements ratherthan detailing such things as

specific ingredients in a compound or a mini-mum weight. This has allowed the manufac-turer to be more creative in both the materialsused and in the overall design of the product.Generally, this has resulted in a more durableand better designed product with a muchmore competitive price. This type of specifi-cation is particularly suited for dealing withnew materials and concepts.

Material Description: Every submissionmust have a detailed description of all materi-als used in the noise barrier structure, includ-ing the standards to which the componentswere manufactured. This would encompasseverything from the panels, posts and footingsdown to the type of fastenings, coatings andother accessory items. In some cases, theagency specifications may stipulate restric-tions on the materials which can be used.Make sure that the restricted materials areavoided in the design, if possible. If not, thenthe onus is on the manufacturer to prove thatit would be of benefit to the agency to allowthe use of the restricted material.

If common construction materials such asconcrete, steel or wood are used, the specificrequirements for these are probably includedin the agency’s noise barrier specifications.However, the recent proliferation of newmaterials generated by the current trend to useplastics and recycled materials has most likelynotbeen specificallyaddressed in the agency’s

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specifications. Many specifications will haveonly general references to these, which gener-ates another instance where the acceptancefundamentals (durability, safety, functional-ity,costeffectiveness)alongwith performancecriteria must be used.

Test Results: Test reports are crucial to anyacceptance process. How tests are conductedand by whom could mean the differencebetween acceptance and rejection of the sub-mission. All testing should be performed by anaccredited, independent testing laboratoryacceptable to the approving agency. On rareoccasions, agencies have permitted testing tobe performed by the manufacturer, but only inthe presence of an agency representativeknowledgeable in the specific test procedure.

Testing should be conducted on full pro-duction run samples, whenever possible. Insome cases, it may be advantageous to havethe approving agency select the samples fortesting. Agencies become cautious when thetests were conducted on samples made spe-cifically for testing purposes.

In selecting a suitable test lab, make surethat the test personnel are familiarwith the testprocedures specific to the material and thefinal product, and insist that they contact theapproving agency to verify these proceduresbefore commencing. The submission shouldinclude complete copies of all required testresults. Names ofthe laboratories, techniciansand telephone numbers should also be pro-vided if the agency wishes to discuss certainaspects of the test results.

Drawings and Associated Notes: Beforestarting the drawings, check with the agencyto see what size is preferred, what details arerequired and in whatformat. But in most casesthe drawings should at least include the fol-lowing items:• Details of individual components• Location and sizes of reinforcing steel in

concrete• Schematic drawing of assembled system• Footingdesign details for installation in earth

and rock• Structure-mounted details• Termination and transition details• Typical grading details• Panel stepping details• Special posts for changes in alignment• Access door and firehose port detailso Type and location of manufacturer’s ID. on

major components

The accompanying notes should include:• Reference wind pressure• Codes to which the barrier was designed• Installation procedures• Noise Reduction Coefficient (NRC)• Sound Transmission Class (STC)• Handling and storage requirements• Physical properties of all materials used• Type of special coatings, stains, etc.

Finally, theyshould be dated, stamped andsigned by a registered professional engineer.

Engineering Calculations: In most areas,the manufacturer is responsible for the struc-

tural integrity of the noise barrier system.Therefore, copies of comprehensive designcalculations must be provided which provethat the panels, posts and footings are capableof withstanding various wind loads and soilconditions in accordancewith the Codes stipu-lated by the approving agency.

Quality Control Plan: The quality controlplan outlines the manufacturer’s proceduresto ensure production of a consistently accept-able product. This document has becomemore of an issue in recent years and should beincluded in all submissions even though thismay not be a compulsory requirement.

Maintenance: Details should be providedto indicate what protection has been used toaddress the graffiti problem and how to restorethe components to their original appearance.Also, in cases ofminor damage, a descriptionof the repair technique should be included.For severe damage situations where the com-ponents must be removed and replaced, themanufacturer should provide a guaranteeddelivery time for replacement parts.

Remember that highway and transporta-tion agencies are always on the lookout fornew and improved materials and systems. Inthe next issue, I will begin to discuss whatmakes an effective noise barrier specification.

Soren Pedersen is a Design Development Analystfor the Ministry of Transportation of Ontario, headoffice located in Toronto, Ontario, Canada. Hemaybe contactedbyphoneat4 16-235-3509, orbyfax at 416-235-5314.

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1991Papers,from page6

to helicopter operations will be well belowmeasured existing ambient noise levels. In-creases of the ambient community noise lev-els (on an Ld, basis) due to helicopter opera-tions will be insignificant. Helicopter opera-tions will sometimes be audible in the vicinityof the hospital, but will occur much lessfrequentlythan theexisting comparablefreighttrain noise events (a maximumof400 helicop-ter annual operations as compared to morethan 18,000 freight trains per year).

Finally, a sound reflection analysis wasundertaken in response to claims of increasedtrain noise near the hospital allegedly due tothe introduction ofthe new hospital wing (thusproviding a potential sound reflective sur-face). This analysis showed that reflections offthe hospital wall are9 to 13 decibels below thedirect path. The level of these reflections addless than 1 decibel to the original signal whichisan insignificantchange. Othervariablesthatmay have contributed to the perception ofincreased noise include I) increased train orbus activity, or 2) increased train noise due touseofdifferentor improperlymaintained equip-ment (such as wheel flats). •

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