Final Report - COH Downtown Simulation

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DOWNTOWN LRT

SIMULATION STUDY

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CITY OF HOUSTON

DEPARTMENT OF PUBLIC WORKS & ENGINEERING

TRAFFIC & TRANSPORTATION DIVISION

December 2010

Photograph courtesy of METRO


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December 2010 Downtown LRT Simulation Study

page i

TABLE OF CONTENTS

EXECUTIVE SUMMARY ................................................................................................. 1Study Findings ........................................................................................................ 1Conclusions ............................................................................................................. 2

INTRODUCTION ............................................................................................................. 3STUDY METHODOLOGY ............................................................................................... 3STUDY RESULTS........................................................................................................... 7CONCLUSIONS ............................................................................................................ 15

TABLESTable 1. Garage Driveways Average Delay Operational Criterion

Table 2. Summary of Observed Performance Measures

FIGURES

Figure 1. Study Limit and Locations

Figure 2. Existing and With LRT Conditions Lane Configurations

Figure 3. LRT Simulation Route and StationsFigure 4. Summary of Average Daily Traffic Counts on Rusk Street and Capitol

Street

Figure 5. Comparison of Average Delay (Day 1)

Figure 6. Comparison of Average Delay (Day 2)

Figure 7. North-South Roadways Investigation Results

APPENDICES

Appendix A. LRT Simulator Buses Time Schedule

Appendix B. Arrival and Departure Data Collection Summary

Appendix C. North-South Streets Blockage Observation Summary


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page 1

EXECUTIVE SUMMARY

METRO is actively working towards the implementation of Light-Rail Train (LRT) linesalong Rusk Street and Capitol Street within the City of Houston downtown area. The purpose of

the downtown LRT simulation study is to determine the level of impact the proposed METRO

light-rail lines may have on the following four car garage driveways along Rusk Street and

Capitol Street. In addition, general operational conditions with LRT simulation weredocumented, in particular the impact of LRT on the north-south roadways within the study limit.

Bank of America building on Smith Street (entrance and exit)

Pennzoil Place building on Capitol Street (exit only)

Esperson Garage on Rusk Street (entrance only)

Heritage Plaza on Rusk Street; or also known as 801 Travis Garage (entrance and exit)

The study methodology was to collect data at the garage driveways to estimate operational

conditions with existing lane configuration and existing traffic control conditions; and then to

compare the results with operational conditions of the garage driveways with LRT simulationusing METRO buses with future lane configuration. The primary performance measure used to

compare operational condition of the garages is average vehicular delay (sec/veh), while the

secondary performance measure used for comparison is maximum back-of-queue (veh) at the

garage driveways. Please note that this study did NOT measure the impact of LRT on thedowntown street network.

In order to capture the typical two primary morning and afternoon peak periods, the projectteam met with building management representatives to determine the morning study hour (7:30

am to 8:30 am), and the afternoon study hour (4:30 pm to 5:30 pm). Data was collected at each

garage driveway for a total of four days to establish two sets of comparison days. The two

existing condition and with LRT simulation comparison days are summarized below.

Day 1 Comparison Tuesday, October 26, 2010 (existing condition), November 09,2010 (with LRT simulation)

Day 2 ComparisonWednesday, October 27, 2010 (existing condition), November 10,

2010 (with LRT simulation)

Study Findings

Table 2 summarizes performance measures collected at the garage driveways. In general,average delay comparison at the driveways on Day 1 and Day 2 are well within an acceptable

level of operation. Figures 5 and 6 also show average delay comparisons of Day 1 and Day 2,respectively in a graphical form. The maximum back-of-queue comparison appears to be withinan acceptable level as well. In addition, the results reflect the operation at the driveways is

highly influenced by the operation of the gate mechanisms and off-duty officers directing traffic;

more than traffic level including LRT on Rusk Street and Capitol Street.


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page 2

Conclusions

In general, average delay comparisons of Day 1 and Day 2 are within acceptableoperational parameters. In addition, the comparisons of the difference between the

existing condition and with LRT simulation average delays are not statistically

significant.

The signal timing and closely spaced signalized intersections within the downtown area

meter traffic entering the driveways, and provide sufficient gaps for exiting traffic from

the driveways. This is the primary reason why high levels of maximum back-of-queues

are not observed at the garage driveways (maximum 4 vehicles). Day 1 and Day 2comparisons did not show a statistically significant difference.

North-south roadways within the study area are congested during the morning andafternoon peak periods mainly due to heavy traffic along the north-south streets. Capitol

Street and Rusk Street traffic appears to not impact the north-south roadways within thestudy limit. During the observation of north-south roadways, we found that off-duty

officers stopping vehicles to facilitate traffic to/from the garages appear to cause back-

ups on Capitol Street and Rusk Street, and in some instances blocking at a maximum onelane of traffic on the north-south streets, but never the entire north-south street. Inaddition, these back-ups almost always clear-out within one cycle period.

In general, the operational levels of the garage driveways seem to be controlled by thegate mechanisms and efficiency of patrons going through the gates. As an example, at

801 Travis garage, the exit lane gate mechanism broke down during an afternoon peakperiod study. Therefore, we had to stop data collection until the gate was functional

again.


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page 3

INTRODUCTION

METRO is actively working towards the implementation of Light-Rail Train (LRT) linesalong Rusk Street and Capitol Street within the City of Houston downtown area. The purpose of

the downtown LRT simulation study is to determine the level of impact the proposed METRO

light-rail lines may have on the following four car garage driveways along Rusk Street and

Capitol Street. Figure 1 illustrates the study area and details of the four garage driveways. Inaddition, general operational conditions with LRT simulation were documented, in particular the

impact of LRT on north-south roadways within the study limit.

Bank of America building on Smith Street (entrance and exit)

Pennzoil Place building on Capitol Street (exit only)

Esperson Garage on Rusk Street (entrance only)

Heritage Plaza on Rusk Street; or also known as 801 Travis Garage (entrance and exit)

The study was conducted in collaboration with various groups within the City of Houstonincluding but not limited to the Mayors Office, Public Works and Engineering Department, and

Parking Management Division. In addition, various outside organizations participated in the

study, including METRO, Houston Downtown Management District, and the buildingsmanagement team. To accomplish the Downtown LRT simulation study; numerous coordination

meetings were held by the participating organizations to complete the study.

STUDY METHODOLOGY

The study methodology is to collect data at the garage driveways to estimate operational

conditions with existing lane configuration and existing traffic control conditions; then to

compare the results with operational conditions of the garage driveways with LRT simulationusing METRO buses with future lane configuration. It is critical to note that this study did NOT

measure the impact of LRT on the downtown street network.

The primary performance measure used to compare operational condition of the garages is

average vehicular delay (sec/veh) while the secondary performance measure used for comparison

is maximum back-of-queue (veh) at the garage driveways. The 2000 Highway Capacity Manual

(HCM) provides models for estimating control delay at unsignalized intersections. A qualitativedescription of the various service levels associated with unsignalized intersections are provided

to evaluate operation of unsignalized intersections. Control delay as described in the HCM

includes deceleration and acceleration delay in addition to resembling stopped-delay at anintersection. Average delay data collected at the garage driveways is not the same as control

delay, but it resembles stopped-delay as described in the HCM. Nevertheless, here are the

reasons why it is different:Delays experienced by vehicles at the garage driveways are heavily influenced by the

operation of the gate mechanism and the familiarity of drivers going through the gates.

Off-duty officers assist vehicles coming in and out of the driveways against conflictingpedestrians and vehicular traffic, which influences delay data collected as part of this

study.

Pedestrian impedance coming in and out of the garage driveways is much higher than the

typical unsignalized intersection operation as described in the HCM.


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Bank of America Ga(entrance

Pennzoil Ga

Esperson Ga(entr

801 Travis Ga(entrance

figure#

1 [Study Limit & Locat

study limit


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page 5

Therefore, the data that was collected as part of this study is simply labeled as average delay(sec/veh), and the following simplified evaluation criterion as shown in Table 1 was developed

to see if the garage driveways are operating within acceptable parameters on Day 1 and Day 2

comparisons.

Table 1

Garage Driveways Average Delay Operational Criterions

Operational Criterion Description of Operational Criterion at the Garage Driveways

GOOD

(0 to 30 sec/veh)

Nearly all drivers find freedom of operation, but some drivers begin to consider the delayan inconvenience.

Very seldom is there more than one vehicle in queue, but occasionally there is morethan one vehicle in queue.

MODERATE

(30 to 40 sec/veh)

Often there is more than one vehicle in queue.

Most drivers feel restricted, but not objectionably so.

CONGESTED

(40 and higher sec/veh)

Represents a condition in which the demand is near or equal to the probable maximumnumber of vehicles that can be accommodated by the driveway, and sometimes it isforced flow of traffic.

There is almost always more than one vehicle in queue and backs-up way beyond the

gate mechanisms.

Drivers find the delays approaching intolerable levels, and sometimes the garagedriveway represents failure in traffic flow.

In order to capture the typical two primary morning and afternoon peak periods, the project

team met with building management representatives to determine the morning study hour (7:30

am to 8:30 am), and the afternoon study hour (4:30 pm to 5:30 pm). Data was collected at eachgarage driveway for a total of four days to establish two sets of comparison days. The two

existing conditions and with LRT simulation comparison days are summarized below.

Day 1 Comparison Tuesday, October 26, 2010 (existing condition), November 09,

2010 (with LRT simulation)

Day 2 ComparisonWednesday, October 27, 2010 (existing condition), November 10,2010 (with LRT simulation)

Existing condition data collection was conducted without much advertisement to the public

to ensure drivers behave naturally within the downtown area. Typical parking restrictions were

allowed as is today during the morning and afternoon peak periods. Figure 2 shows the existinglane configuration of Rusk Street and Capitol Street when data was collected at the garage

driveways for existing condition.

Data collection with LRT simulation was conducted using three buses as two sets of LRT

simulators. The following additional measures were implemented to simulate conditions as it isplanned to be after implementation of the proposed LRT.

Parking meters along Rusk Street and Capitol Street within the study limit werebagged by the Parking Management Division.

Lane reduction due to the proposed LRT implementation along Rusk Street and

Capitol Street was achieved by using traffic control cones during the study periodsbased on the proposed pavement marking plan provided by METRO. Figure 2 shows

lane configuration with LRT simulation condition.

All construction related lane closures were kept the same within the study limit.


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figure #2 [Existing & With LRT Conditions Lane ConfiguratiLane Clo

(with LRT Condit


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page 7

Figure 3 shows the LRT simulation route and the proposed LRT station locationswhere simulator buses stopped to simulate the proposed LRT lines. The average

dwell time LRT simulator buses stopped at the proposed stations was 20 seconds.

Appendix A shows time schedule of simulator buses that METRO provided to the

City of Houston, which indicates a service frequency of 6 minute runs. Two sets of

LRT simulators (the first set with two buses and the second with one bus) run thesimulation route, stopping at the proposed LRT stations every 6 minutes.

Existing signal timing plan was not altered and LRT simulator buses used the most

southern lanes on Rusk Street and Capitol Street, sharing the lane with vehicular

traffic.

Data collection was performed at each garage driveway using arrival and departure timestamp software on a laptop computer. In case the data collection results were compromised on

the laptop computer, the study team used a digital video recorder as a backup feature. Thesoftware is capable of recording arrival and departure time stamps using the computer master

clock, which allows computation of average delay, maximum back-of-queue, and the number of

vehicles at the garage driveways.

Arrival times for entrance driveways were recorded exactly when a vehicle reached the

standing queue and stopped; or if there are no queue present, when the front of the

vehicle crossed over the curb line.

Departure times for entrance driveways were recorded when the back of the vehiclecrossed over the curb line and approached the gate mechanism.

Arrival times for exit driveways were recorded exactly when a vehicle reached thestanding queue and stopped; or if there are no queue present, when the front of the

vehicle reached the curb line.

Departure times for exit driveways were recorded when the back of the vehicle crossed

over the curb line.

STUDY RESULTS

Table 2 summarizes average delay (sec/veh), maximum back-of-queue (veh), and thenumber of vehicles per hour at each garage driveway for each peak study time period for Day 1

and Day 2 comparisons. Appendix B contains raw data and calculation of the performance

measure outputs that are presented in Table 2. The level of traffic demand along Rusk Street and

Capitol Street, as summarized in Figure 4, appear to be ideal conditions for comparison of Day 1and Day 2 conditions to quantify and analyze the impact of the proposed LRT lines on the

operation of the four garage driveways.


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Table 2Summary of Observed Performance Measures

Day 1 Comparison - Tuesday October 26 (Existing Condition) and November 09 (With LRT Simulation)

MORNING PEAK PERIOD AFTERNOON PEAK PERIOD

Maximum Back of Queue Number of Vehicles Average Delay (sec/veh) Maximum Back of Queue Number of Vehicles Average Delay (se

GarageExisting

ConditionsWith LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

WitSim

Esperson Garage Entrance 3 3 164 166 13.7 13.8 0 1 10 12 2.8

801 Travis Garage Entrance 4 3 131 112 15.1 14.6 N/A N/A N/A N/A N/A N

801 Travis Garage Exit N/A N/A N/A N/A N/A N/A 1 3 118 99 9.4

Bank of America GarageEntrance

1 1 101 93 4.1 4.7 0 0 24 19 5.1

Bank of America Garage Exit 0 0 4 3 22.8 (1) 13.9 1 3 69 78 10.9

Pennzoil Garage Exit (1) 0 0 5 4 7.1 6.6 2 3 102 99 13.8 2

Daily Average 2 1 82 76 15 11 1 2 65 61 8

Day 2 Comparison - Wednesday October 27 (Existing Condition) and November 10 (With LRT Simulation)

MORNING PEAK PERIOD AFTERNOON PEAK PERIOD

Maximum Back of Queue Number of Vehicles Average Delay (sec/veh) Maximum Back of Queue Number of Vehicles Average Delay (se

GARAGESExisting

ConditionsWith LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

With LRTSimulation

ExistingConditions

WitSim

Esperson Garage Entrance 3 2 150 146 18.2 10.9 0 1 14 9 3.8

801 Travis Garage Entrance 4 4 148 143 14.7 13 N/A N/A N/A N/A N/A N

801 Travis Garage Exit N/A N/A N/A N/A N/A N/A 3 4 117 82 (2) 9.2

Bank of America GarageEntrance

1 1 90 104 4.7 6.1 1 0 50 19 5.7

Bank of America Garage Exit 0 0 4 5 10 13.1 3 0 68 3 19.7

Pennzoil Garage Exit(1)

0 0 11 3 7.1 14.6 3 3 100 108 12.2

Daily Average 2 1 81 80 11 12 2 2 70 35 10

Notes:

(1) Garage security personnel stopped the four vehicles to clear heavy pedestrian traffic.(2) Due to the garage gate mechanism malfunction data collection was suspended for a while. Actual number of vehicles within the hour is 106.(3) Off-duty officer held up driveway traffic to assist pedestrian trying to flag a cab.


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METRORail Sta

1 Capitol, bet

Louisiana &

2 Rusk, bet

Bagby &

Staging A

1 Rusk, bet

Bagby &

2 Capitol, betMain &

figure#3 [LRT Simulation Route & Stati

rail route


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Existing | LRT Simul

6863

Capitol, bet

Main &

7694

Capitol, bet

Milam & Lou

8172

Rusk, bet

Louisiana & M

4864

Rusk, bet

Travis &

figure#4 [Summary of Average Daily Traffic Counts on Rusk Street & Capitol Str

7694 7088

8172 6298

6863 7607

4864 5477


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The primary performance measure used to compare the operational condition of thegarage driveways is average vehicular delay (sec/veh). In general, average delay comparisons of

Day 1 and Day 2 are within acceptable operational parameters. As Table 2 shows, on average,

the comparisons of Day 1 and Day 2 are not statistically significant to quantify the impact ofLRT on the operation of the garage driveways. As Figures 5 and 6 show, Day 1 and Day 2

comparisons respectively, the garage driveways are operating GOOD. Sometimes, when thereare other influencing factors such as off-duty officers, gate mechanism malfunction, and heavy

pedestrian traffic, the driveways may operate MODERATE during both existing and with LRTconditions. In addition, back-of-queues are well within acceptable parameters at the garage

driveways (maximum 4 vehicles) during Day 1 and Day 2 comparisons, which do not show a

statistically significant difference.

Another item that was observed in the field during the existing and with LRT conditionswas the impact of the proposed LRT on north-south roadways within the study area. This was

accomplish simply by observing all signalized intersections within the study limit, and then

documenting how many times during the analysis period north-south streets were blocked due totraffic on Rusk Street and Capitol Street. A single investigator observed one signalized

intersection and filled out a form documenting how many times a blockage of north-southroadway occurred due to traffic spill-back of Rusk Street and Capitol Street. Appendix Cincludes observation results of each intersection. Below are the results of our observation and

Figure 7 illustrates potential queue spill-backs that may occur due to LRT implementation.

During both existing and with LRT conditions in comparison Day 1 and Day 2, completeblockage of north-south roadways due to traffic on Rusk Street and Capitol Street was not

observed. The north-south streets within the study limit are congested primarily due tothe large number of vehicles that are coming to downtown in the morning and leaving

downtown in the afternoon peak periods.

With LRT simulation condition including the reduction of one eastbound lane on the westapproach of Rusk Street/Milam Street intersection caused seven spill-back queues during

the morning peak period that extended back to block only the northbound diamond-laneat the intersection of Louisiana Street/Rusk Street. All seven spill-backs pretty much

dissipated within one cycle and the queue spill-back did not block northbound through

traffic lanes of Louisiana Street at any time.

Due to the combination of the proposed LRT station on the east approach and theproposed removal of exclusive westbound left-turn lane at the intersection of Smith

Street/Capitol Street, queue spill-back through the intersection of Louisiana

Street/Capitol Street was observed when LRT simulators were dwelling at the proposedstation location. The queue was mainly isolated along the northbound exclusive left-turn

lane at the intersection of Louisiana Street/Capitol Street. The spill-back queue

dissipated within one cycle and it did not impact the northbound through traffic lanes ofLouisiana Street at any time.


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13.7

15.1

N/A

4.1

22.8

7.1

13.814.6

N/A

4.7

13.9

2.8

N/A

9.4

5.1

10.911.1

N/A

11.7

3.6

18.7

0

10

20

30

40

50

60

Esperson Entrance 801 Travis Entrance 801 Travis Exit Bank of America

Entranc e

Bank o f America Exit P

figure#5 [Comparis


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18.2

14.7

N/A

4.7

10

7.1

10.9

13

N/A

6.1

13.1

3.8

N/A

9.2

5.7

19.7

11.2

N/A

16.3

2.5

14.6

0

10

20

30

40

50

60

Esperson Entrance 801 Travis Entrance 801 Travis Exit Bank of America

Entranc e

Bank o f America Ex it P

figure#6 [Comparis


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LRT at Propo

Sta

Propo

Sta

Vehicle

Qu

Lane Clo

(with

conditCapitol

Bagby

Smith

Louisiana

Milam

Rusk

figure#7 [North-SouthRoadways InvestigationResu

1

2

The Rusk Street/Milam Street intersection caused seven spill-back queues during

morning peak period that extended back to block only the northbound diamond-

at the intersection of Louisiana Street/Rusk Street.

At the shared LRT and vehicular lane of the Smith Street/Capitol Street intersection,

queue build-up through the intersection of Louisiana Street/Capitol Street was observed

when LRT simulators were dwelling at the proposed station location.


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CONCLUSIONS

In general, average delay comparisons of Day 1 and Day 2 are within acceptableoperational parameters. In addition, the comparisons of the difference between existing

conditions and with LRT simulation average delays are not statistically significant.

The signal timing and closely spaced signalized intersections within the downtown areameter traffic entering the driveways, and provide sufficient gaps for exiting traffic from

the driveways. This is the primary reason why high levels of maximum back-of-queues

are not observed at the garage driveways (maximum 4 vehicles). Day 1 and Day 2

comparisons did not show a statistically significant difference.

North-south roadways within the study area are congested during the morning andafternoon peak periods mainly due to heavy traffic along the north-south streets. Capitol

Street and Rusk Street traffic appears to not impact the north-south roadways within the

study limit. During the observation of north-south roadways, we found that off-dutyofficers stopping vehicles to facilitate traffic to/from the garages appear to cause back-

ups on Capitol Street and Rusk Street and, in some instances, block at a maximum one

lane of traffic on the north-south streets, but never the entire north-south street. Inaddition, these back-ups almost always clear-out within one cycle period.

In general, the operational levels of the garage driveways seem to be controlled by thegate mechanisms and efficiency of patrons going through the gates. As an example, at

801 Travis garage, the exit lane gate mechanism broke down during an afternoon peak

period study. Therefore, we had to stop data collection until the gate was functionalagain.


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APPENDIXLRT Simulator Buses Time Sched

RAIL SIMULATION

NOVEMBER 2010


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APPENDIX

Arrival and Departure Data Collection Summ


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APPENDIXNorth-South Streets Blockage Observat

Summ

Final Report - COH Downtown Simulation

Documents

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