estimating work zone performance measures on signalized arterial · pdf file ·...

Estimating Work Zone

Performance Measures

on Signalized Arterial

Arterials

Minneapolis, MN

Prepared By:

Alliant Engineering, Inc.

233 Park Avenue South, Suite 300

Minneapolis, MN 55415

Prepared For:

Minnesota Department of Transportation

Final Report

May 30, 2016

Estimating Work Zone Performance

Measures on Signalized Arterials

i Alliant 114-0136.0

Table of Contents Executive Summary ...................................................................................................................................... iii

1 Introduction .......................................................................................................................................... 1

2 System Overview................................................................................................................................... 1

3 Performance Measures ......................................................................................................................... 2

3.1 Literature Search ........................................................................................................................... 2

3.2 MnDOT Current Practice ............................................................................................................... 3

3.3 Performance Measures for this Project ........................................................................................ 3

4 Corridor Selection ................................................................................................................................. 5

4.1 Construction Activities on and around Highway 55...................................................................... 7

5 Implementation .................................................................................................................................... 7

6 Monitoring ............................................................................................................................................ 8

6.1 Baseline Conditions ....................................................................................................................... 8

6.2 Monthly Reports ........................................................................................................................... 8

6.3 I-394 Westbound Lane Closure ..................................................................................................... 9

6.4 I-394 Eastbound Closure ............................................................................................................... 9

6.5 Performance Measure Comparison ............................................................................................ 10

7 Lessons Learned .................................................................................................................................. 17

7.1 Success Stories ............................................................................................................................ 17

7.2 Problems Encountered ............................................................................................................... 17

7.3 Best Practices Related to SMART-Signal ..................................................................................... 18

7.4 Monitoring Work Zone Performance Measures on Future Projects .......................................... 18

8 APPENDIX ............................................................................................................................................ 20



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List of Tables

Table 3.3.1 Urban Street Level of Service Criteria ........................................................................................ 4

Table 6.5.1 Baseline Travel Times ............................................................................................................... 11

Table 6.5.2 Baseline Arterial Level of Service ............................................................................................. 12

Table 6.5.3 Travel Times during Westbound I-394 Closure ........................................................................ 13

Table 6.5.4 Arterial Level of Service during Westbound I-394 Closure ...................................................... 14

Table 6.5.5 Travel Times during Eastbound I-394 Closure.......................................................................... 15

Table 6.5.7 Arterial Level of Service during Eastbound I-394 Closure ........................................................ 16

List of Figures

Figure 4.1 Project Location Map ................................................................................................................... 6



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Executive Summary

Work zones can cause significant traffic congestion and safety impacts. Work zone performance

measures help agencies improve their understanding of how their decisions during planning, design, and

construction affect work zone safety and mobility. Performance measures on signalized arterial

corridors are difficult to measure because of the variability caused by traffic signal operations. New

traffic signal technologies are emerging that collect and utilize high resolution data to produce

performance measures on signalized arterials. The basic operational concept is to use a High Resolution

Monitoring System (HRMS) to monitor work zone operations on a signalized arterial corridor and

document performance measures such as delays and travel time. When specific performance measure

thresholds are reached (such as a 15 minute increase in travel time delay), the Traffic Engineer may

choose to take action to mitigate the delay, such as adjusting signal timing or implementing other traffic

control measures to improve operations.

SMART-Signal is one example of the High Resolution Monitoring System described above. SMART-Signal

has been deployed by MnDOT at a number of signalized intersections, primarily within the Metro

District. This project utilized SMART-Signal to monitor work zone performance on TH 55 during the 2015

construction season.

Performance Measures and Thresholds

Based on the literature search and MnDOT practice, it was determined to utilize increase in travel time

delay as the primary performance measure. Based on MnDOT practice, the threshold to signify

significant congestion is an increase in the travel time delay by 15 minutes for a corridor longer than one

mile. Another performance measure that will be considered for this project is Arterial Level of Service

(LOS). The Highway Capacity Manual provides LOS criteria based on a percentage of the free flow speed.

A drop in arterial operations below LOS E, or a drop of two letter grades, will be considered indicators of

congestion.

Corridor Selection

After review of several potential candidates, the Highway 55 corridor was selected. The corridor

extended from Theodore Wirth Parkway to Arrowhead Drive, and included 26 intersections. Although

no substantial physical construction was planned on Highway 55, Highway 55 would serve as a diversion

route for two nearby construction projects: I-494 and I-394.

System Implementation and Baseline Data

The implementation of SMART-Signal included installation of a device in each cabinet (Adaptitrol) which

allows SMART-Signal to monitor intersection operations. The communication system utilized two

strands of unused fiber from MnDOT that connected each of the intersections back to the Regional

Traffic Management Center (RTMC). SMART-Signal staff also worked closely with Alliant staff to further

develop the software interface (iMeasure) to provide greater flexibility in data manipulation and

reporting. The system was up and running at all 26 intersections by the end of March 2015. A baseline

report was created prior to construction beginning on the corridor. Volumes, Intersection Delay and

LOS, maximum queue length, Arterial LOS, and Travel Time were documented for a typical weekday,

Saturday, and Sunday.



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Monitoring of Work Zone Events on I-394

The Alliant Team monitored traffic conditions on a weekly basis, and prepared monthly reports

summarizing the results. In general, the existing signal timing plans on TH 55 were able to effectively

handle changes in traffic volumes, and only minor changes in travel time and delay were noticed.

The I-394 reconstruction project had two significant events that were analyzed in more detail. For two

weeks in July, construction occurred on the westbound lanes of I-394. I-394 westbound traffic was

placed in the HOV/HOT lanes between downtown and TH 100. The eastbound general purpose lanes

remained open, but included all eastbound traffic, including HOV. For two weeks in early August,

construction occurred on the eastbound lanes of I-394. I-394 eastbound traffic was placed in the

HOV/HOT lanes between downtown and TH 100. The westbound general purpose lanes remained open,

but included all westbound traffic, including HOV.

The SMART-Signal system was utilized to develop travel time and travel speed estimations for the peak

periods. Manual travel times were also conducted by Alliant staff to verify the performance of the

system. For the two events on I-394, data on TH 55 was gathered and compared to the two performance

measure thresholds:

• Increase in travel time delay by more than 15 minutes

• A significant drop in arterial LOS (from LOS E to LOS F, or a drop of two letter grades)

During the Westbound I-394 lane closure, the increase in travel time delay during both peak periods was

less than 15 minutes in both directions. Therefore, the threshold for enhanced mitigation measures was

not reached. The arterial LOS remained LOS D or better, which also did not reach the threshold for

enhanced mitigation measures. However, specific segments reached LOS F, which could signify the need

for additional mitigation, including modification of the signal timing plan.

The Eastbound I-394 lane closure provided similar results. While travel time delay did increase to 13

minutes, it fell short of the 15 minute threshold. Similarly, the overall arterial operations remained at

LOS D or better. However, specific segments dropped to LOS F, which could signify the need for

mitigation measures.

Lessons Learned

SMART-Signal, and its performance measure software, iMeasure, is a powerful tool that can document

travel time and delay. The system’s travel time estimation algorithm is accurate under most conditions.

Manually collected travel time data verified the accuracy of the system as part of this project.

Both travel times and arterial level of service (travel speed) are known performance measures that can

quantify corridor performance and impacts. In particular, arterial level of service can not only identify an

impact, but can also provide an understanding of the level of impact when compared to normal

conditions.

Travel time estimation on signalized arterial corridors is more complex than on freeways. The signal

delay adds in variability under normal conditions. Travel times should be reported as a range to account

for this variability. Changes in the 85th percentile travel times should be used to indicate increased

congestion.

The Highway 55 corridor proved to be capable of handling changes in traffic volumes within its normal

signal operations plan under most conditions. The iMeasure system provided validation that the corridor

was operating under acceptable parameters.



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Problems Encountered

The availability and consistency of data is extremely important. Communications between traffic signals

and the data server must be maintained at all times. If communications are lost, data is not available to

calculate travel times or to compare other performance measures.

The signalized arterial corridor cannot include intersections controlled as all-way stops (either signed or

if signals are on red flash). The algorithms to calculate travel times, intersection delay, and queuing do

not work under this scenario.

Overall, the iMeasure systems appears to be accurate when measuring performance measures.

However, there were some instances (bad weather, incidents blocking lanes) that caused high levels of

queuing and congestion. Under these circumstances, iMeasure underestimated the level of congestion

(travel times, queuing, delays).

Best Practices

The system should be checked frequently to confirm that all traffic signal equipment and

communications are operating properly. When problems are encountered, the issue should be rectified

as soon as possible, or at least noted so that the reason for missing data is understood.

On future projects, data could be used to modify the time-of-day signal timing program to better

address changes in traffic flows caused by construction. Under extreme circumstances with long

durations, this data could also be used to develop new signal timing plan.

The system could be used to validate traffic complaints (both for corridors under construction and

“normal” corridors). When a complaint is received, information such as delay, queuing, and travel time

can be reviewed from the time period in question to determine if a problem existed.

Based on the experience of this project, the group discussed developing a methodology that could be

used on projects in the future. The steps identified in Section 7.4 provide a high level summary of a

process that could be followed.



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1 Introduction

Work zones can cause significant traffic congestion and safety impacts. Agencies strive to manage these

impacts as best possible to meet the needs of its customers, complete the project effectively, and

support regional mobility and the economy. Agencies can systematically assess work zone impacts by

utilizing performance measures. Work zone performance measures help agencies improve their

understanding of how their decisions during planning, design, and construction affect work zone safety

and mobility, and thus can help improve how they make decisions for future work zones. During a

project, performance measures can be used to actively manage traffic operations, and to provide travel

time and delay information to the public. Two frequently used performance measures for traffic

operations are queue lengths and travel time delay. Accurate measurements of travel time delay can

also be shared with the traveling public as a travel demand management tool, allowing the driver to

choose their route based on current travel time and delay information.

Performance measures on signalized arterial corridors are difficult to measure because of the

variability caused by traffic signal operations. Typical methods used on freeways to measure travel time

delay include estimating travel time from manually measured queue lengths or travel time runs.

Another method utilizes spot sensors to estimate speed and queue length. While these methods work

well for freeways, their accuracy and effectiveness on signalized arterials is limited, because they cannot

account for the signal delay. Other methods that track vehicles through a system, such as Bluetooth or

Sensys, are expensive to implement as a work zone management tool, and still have issues with

accuracy.

Traffic signal technologies are emerging that may provide additional information related to work zones.

Technologies that are being developed include systems that collect and utilize high resolution data to

produce performance measures on signalized arterials. The basic operational concept is to use a High

Resolution Monitoring System (HRMS) to monitor work zone operations on a signalized arterial corridor

and document performance measures such as change in volume, queues, saturation flow rates, delays,

and travel times. When specific performance measure thresholds are reached (such as 10 minute

increase in delay or travel time), data from the HRMS will be utilized to identify the delay, and to adjust

signal timing or identify other traffic control measures (such as closing specific turn movements or

intersections) to improve operations.

2 System Overview

A system that utilizes a High Resolution Monitoring System (HRMS) to monitor work zone performance

will include the following features:

• Controller Interface - Collects controller and detector data from each intersection directly from

the controller. If the controller is not equipped to permit the collection and communication of

requisite data, a NEMA-compliant retrofit kit for 170/2070, TS1 and TS2 type controllers is

installed. It is a plug and play device that easily slides into the controller cabinet. The kit permits

the collection of data from all detector types including loop, video and radar devices and from all

manufactures of controller.

• Communications - The data from each traffic signal is retrieved to a database server. The

preferred communications method is over fiber optic cable. However, cell phone communications

can be used if hard-wire connections are not available.



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• Performance Measure Analysis – The HRMS would include an algorithm that uses the actual

traffic data collected to calculate an algorithmic model of traffic behavior, queue lengths, and

travel times. The software also calculates other performance measures such as saturation flow

rates and intersection delay

• Software and User Interface – The HRMS includes software and a user interface that can be used

to create data collection and performance measure reports.

• Additional Detection – The HRMS requires that the signal system has mainline detection in

advance of the intersection. If this detection is not present, additional temporary detection would

need to be installed.

SMART-Signal is one example of the High Resolution Monitoring System described above. SMART-Signal

has been deployed by MnDOT at a number of signalized intersections, primarily within the Metro District.

It is used to monitor performance on signalized arterials, and to gather data used for signal optimization.

SMART Signal Technologies, Inc. helps improve traffic on signalized arterial corridors by offering a set

of technologies for the Systematic Monitoring of Arterial Road Traffic that permits calculation of accurate

queue lengths and travel times using existing installed infrastructure augmented by the company's

proprietary Queue Length Processing (QLP) algorithms to provide Real Time Performance

Measures. SMART Signal technology has been implemented on several MnDOT corridors and has been

found to be a relatively reliable source for traffic volume, vehicle queues, and arterial travel time

information. Further software enhancements have created tools that can provide a historic model of

system performance, and tools that can provide traffic engineers with information that can assist in

identifying and diagnosing problems in signal operations.

A Systems Engineering analysis, including a Concept of Operations, was developed for the project and is

included in the appendix.

3 Performance Measures

3.1 Literature Search In the FHWA’s A Primer on Work Zone Safety and Mobility Performance Measurement, the three main

categories of work zone performance measures are:

• Exposure measurements: the amount of time, work activity periods, roadway space, and/or

vehicle travel that a work zone affects.

• Safety measurements: how a crash risk has changed for individual motorist and/or traveling

public.

• Mobility measurements (traffic operations): how travel mobility has been affected for motorists

(and other types of travelers). (FHWA, 2011)

The FHWA’s Primer also notes that monitoring urban arterial roadways are more complex than freeway

work zones, due to delays from signals and other traffic control devices. It suggests that local agencies

to establish freeway measures before moving onto arterial work zones. (FHWA, 2011). This project will

focus on the third bullet above, documenting how mobility has been affected by construction activities.

Technical Memorandum No. 1, Current Policies and Practices, is included in the appendix. The Technical

Memorandum summarizes both the national literature search and a summary of MnDOT Current

Practice.



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3.2 MnDOT Current Practice MnDOT has primarily focused on freeway elements when evaluating performance measures in work

zones. The two most frequently utilized measures are change in traffic volume, and travel times (added

delay). MnDOT has summarized performance measures (travel times) on a frequent basis on other

construction projects. MnDOT uses system detector data to monitor traffic volumes on signalized

corridors. They have also conducted manual travel time runs. MnDOT Traffic uses FREEVAL and

QUICKZONE to analyze freeways, and Synchro for arterials.

Another challenge in estimating work zone impacts is determining the amount of traffic that will divert

away from work zone before it happens. Simplistic methods for estimating traffic exist, such as the 1/3-

1/3-1/3 rule (1/3 of traffic stays on the route under construction, 1/3 diverts to the detour route or

other logical route, 1/3 changes time or pattern completely). However, MnDOT typically relies on the

regional travel demand model to estimate diversion levels.

MnDOT typically prepares a Transportation Management Plan that establishes threshold to trigger

enhanced mitigation efforts. Some mitigation occurs during design. MnDOT uses the following

thresholds for both arterials and freeways:

• Less than 1 mile – 10 minutes added delay

• More than 1 mile – 15 minutes added delay

MnDOT’s signal operations group monitors corridors that are under construction by utilizing cameras (if

available) to frequently monitor operations. They also rely on field reviews, and calls received from the

public. On occasion, new timing plans have been developed, if construction activities will impact the

corridor is a consistent manner for an extended period of time. Signal coordination is maintained by

manually synching local clocks if interconnect is not available.

Where possible, the TMP should address and consider mitigation measures ahead of time. This was

done successfully on the recent TH 61 project, where temporary improvements such as dual lefts, free

rights, and turn lane extensions were added to the traffic control plans. Mitigation measures can be

identified through a TMP, or with institutional knowledge of system.

3.3 Performance Measures for this Project Based on the literature search and MnDOT practice, it was determined to utilize travel time and change

in traffic volume as the two primary performance measures. Because of the capabilities of the SMART-

Signal system, it was also determined to monitor and document queue lengths and intersection delay.

Because travel time on a signalized corridor can be variable based on how a vehicle is impacted by signal

delay, the travel time will be reported as a range based on best case/worst case travel times, estimated

by the 15th and 85th percentiles.

The threshold to signify significant congestion or delay would be an increase in the 85th percentile travel

time by 15 minutes, if the corridor is longer than one mile.



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Another performance measure that could be considered is Arterial Level of Service (LOS). The Highway

Capacity Manual, Chapter 16/Urban Street Facilities, provides level of service criteria based on a

percentage of the free flow speed. Table 3.3.1 below summarizes the level of service criteria as a

percentage of Base Free Flow Speed. The table also includes values for free flow speeds of 55 mph and

50 mph, which are found on the TH 55 corridor.

These criteria can measure a drop in level of service that may trigger enhanced mitigation efforts, and

could also provide guidance regarding the magnitude of the mitigation effort. In an urban area, the LOS

D/E boundary is typically considered the indicator of congestion on arterial signalized corridor. Work

zone activities resulting in a decrease in performance from LOS C to LOS D may require little or no

action. However, work zone activities resulting in a decrease from LOS to LOS F may require enhanced

mitigation efforts.

Table 3.3.1

Urban Street Level of Service Criteria



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4 Corridor Selection The locations selected for implementing the Estimating Work Zone Performance on Signalized Arterials

system would be determined by input from Signal Operations and Work Zone Management staff. Ideal

corridor locations include two scenarios:

• Scenario 1: Signalized arterial under construction (work zone impacts available capacity and

operations on roadway)

• Scenario 2: Signalized arterial impacted by adjacent construction (traffic volumes increase

because route used as official or unofficial detour route)

In addition, because of the specific constraints of this project, construction needed to occur in 2015 and

last at least two months, preferably longer. The project budget assumed one corridor of 10

intersections, or two corridors of five intersections. After review of several potential candidates, the

Highway 55 corridor was selected. The key characteristics of Highway 55 are listed below:

• The corridor extends from Theodore Wirth Parkway on the east to Arrowhead drive on the west

(approximately 13 miles). See Figure 4.1

• The corridor included 26 intersections which was larger than originally planned. However, 10 of

the intersections were already equipped with the SMART-Signal equipment, and it was

determined to move forward with this corridor.

• There will not be substantial physical construction on Highway 55, except for a few short-term

projects.

• However, Highway 55 would serve as a diversion route for two nearby construction projects:

o I-494 will be under construction between I-94 and I-394, and Highway 55 would serve as

an alternate route.

o I-394 will be under construction between downtown and TH 100, and Highway 55 would

be posted as an alternate route for several major closures.



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Figure 4.1

Project Location Map



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4.1 Construction Activities on and around Highway 55 The table below summarizes all of the construction projects that could affect traffic operations on

Highway 55 during 2015. The project team tracked the construction projects to help understand the

impacts.

Project

Number

Location Start/End Dates Description of Impacts / Website

2723-123 TH 55 – I494

to Plymouth

Blvd

7/06/15-8/23/15 Add 3rd Lane WB, Lane Closures

mndot.gov/metro/projects/hwy55plymouth/

2785-330 I-494 in

Plymouth

4/13/15-

11/15/15

Repair pavement, bridge decks and ramps, and add a

third lane between Hwy 55 and the I-94/694

interchange

mndot.gov/metro/projects/i494plymouth/

2735-198 TH 100 in

Golden Valley

at TH 55

August-October Extend northbound exit ramp to Hwy 55 and turn

lanes; Ramp and shoulder closures

2734-33 TH 100 in St.

Louis Park

between Cedar

and 36th Street

April-November Interchange reconstruction; Lane Closures, full

weekend closures, detours

mndot.gov/metro/projects/hwy100slp/

2789-136 I-394 between

I-94 and TH

100

June-September Resurface I-394 and frontage roads; reconstruct

Lyndale Ave bridge. Major impacts, two weeks in

each direction (Jul-Aug); weekend and night impacts

all summer

mndot.gov/metro/projects/i394minneapolis/

Vicksburg

Lane North of

Rockford

Road

2015 Reconstruction with Closures

Revere Lane 2015 Mill and Overlay of neighborhood south of TH 55

5 Implementation The SMART-Signal system was set up to be completely independent of the traffic signal control system.

With the assistance of MnDOT staff, the project team implemented the SMART-Signal system on the TH

55 corridor. The implementation included installation of a device in each cabinet (Adaptitrol) which

allows SMART-Signal to monitor intersection operations. The communication system utilized two

strands of unused fiber from MnDOT that connected each of the intersections back to the Regional

Traffic Management Center (RTMC), relaying information to a special SMART-Signal server housed at the

RTMC.

SMART-Signal staff also worked closely with Alliant staff to further develop the software interface

(iMeasure) to provide greater flexibility in data manipulation and reporting. The system was up and

running at all 26 intersections by the end of March 2015.



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6 Monitoring

6.1 Baseline Conditions A baseline report was created prior to construction beginning on the corridor. The time period from

3/28/15 to 4/03/15 was chosen for the baseline week. The following bullets summarize the baseline

condition:

• Volumes: Overall, traffic patterns show that volumes reflect commuter-based traffic, with peaks in

the AM and PM peak hours. Among the volume count locations, volumes are highest west of I-494,

peaking at over 600 vehicles per 15-minute interval in the AM peak. Weekend traffic varies by

location and time of day, but generally, Saturday volumes are higher than Sunday.

• Intersection Delay and Intersection LOS: In analyzing all approaches, most of the intersections

operate an acceptable LOS. In analyzing minor approaches, delays are much more significant along

the corridor. Heaviest delays are seen in the AM and PM peak periods, with the worst delays shown

between Highway 100 and South Shore Drive, as well as Fernbrook Lane to Sioux Drive. The worst

interchanges operate mostly around LOS E/LOS F during the peak periods.

• Maximum Queue Length: Overall, most intersections along the TH-55 corridor have an acceptable

queue length at the eastbound and westbound approaches. During the AM peak period, Niagara

Lane/Plymouth Boulevard experiences heavier queuing eastbound, at times pushing past the

storage of the turn pockets. Peony Lane also sees longer queues in the AM, with some queues that

may block turn lane pockets. In the PM peak period, heavy queuing westbound is observed at the

TH-494 East Ramps and at Fernbrook Lane. Storage for westbound Fernbrook is limited due to its

close proximity to the TH-494 West Ramp, which is about 725 feet away. Additionally, Sioux Drive

westbound in the PM peak experiences heavier queuing, with some queue lengths extending

beyond the turn lane pockets.

• Average Speeds/Arterial LOS: Overall, the corridor operates at an acceptable LOS in both the AM

and PM peak hours, ranging in speeds of about 30-38 mph (LOS B/C). Heavier delays are seen

westbound between Theodore Wirth Parkway and TH-100 (east end of corridor) in both the AM and

PM peak, where the average speeds are about 26 mph (LOS C/D).

• Travel Time: Eastbound travel time for the full corridor in the AM peak ranges from 19-23 minutes,

while the PM peak ranges from 21-26 minutes. In the westbound direction, corridor travel time in

the AM is 21-26 minutes, while the PM is nearly 21-25 minutes. Typical delay from traffic signals

ranges from 5-12 minutes based on a free flow travel time of 14 minutes.

6.2 Monthly Reports The Alliant Team monitored traffic conditions on a weekly basis, and prepared monthly reports

summarizing the results. In general, the existing signal timing plans were able to handle changes in

traffic volumes, and only minor changes in travel time and delay were noticed. This was not unexpected,

since most of the construction impacts did not directly affect conditions on TH 55.

However, the I-394 reconstruction project had two significant events that were analyzed in more detail,

since the activities greatly impacted operations on TH 55. Between 7/13 and 7/27, construction

occurred on the westbound lanes of I-394. I-394 westbound traffic was placed in the HOV/HOT lanes

between downtown and TH 100. The eastbound general purpose lanes remained open, but included all

eastbound traffic, including HOV. Between 8/03 and 8/14, construction occurred on the eastbound lanes

of I-394. I-394 eastbound traffic was placed in the HOV/HOT lanes between downtown and TH 100. The

westbound general purpose lanes remained open, but included all westbound traffic, including HOV.

All of the monthly reports are included in the appendix.



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6.3 I-394 Westbound Lane Closure Volume, average speed, and travel time data was collected for the week of July 13, 2015 from the

iMeasure system and was summarized in tables and charts.

• iMeasure data indicated that westbound traffic volumes doubled along the east end of the TH

55 corridor.

• iMeasure reported slightly higher travel time data than baseline week travel time data.

• iMeasure reported little change in arterial travel speed, and no change in LOS.

Alliant also conducted field observations and manual travel time runs to provide additional data, and to

verify how well SMART-Signal addressed congested conditions.

• The SMART-Signal travel time data compared well with field collected data, except for the

westbound direction in the PM peak.

• For the WB direction in the PM peak, SMART-Signal was found to have underreported travel

times during very congested conditions, when compared to actual data collected in the field.

Alliant conducted field observations along the TH 55 corridor during the closure. All of the observations

below reflect PM Peak traffic conditions.

o Getting out of downtown Minneapolis was very difficult for westbound I-394 traffic as it

was forced down to one lane in order to get all of this traffic onto the HOV lanes.

o Heavy westbound TH 55 congestion from Penn Ave to Bryant Ave. Penn Ave was not

clearing the queue and created a pinch point.

o Heavy westbound TH 55 congestion from Winnetka Ave to Douglas Dr.

o Heavy westbound TH 55 congestion from Revere Lane to east of TH 169.

o Heavy westbound TH 55 congestion from Fernbrook Lane to County Road 6 due in part

to a weaving area just west of Northwest Blvd.

The group discussed possible mitigation measures that could have been implemented. The most

effective mitigation would be to adjust the time-of-day pattern to better fit the changes to the traffic

volume profile caused by the traffic diversion. Adjusting the time of day pattern could be accomplished

with minimal effort, and would still rely on timing plans previously created. Adjusting the time of day

plan could improve traffic flow by beginning a higher cycle / higher volume traffic signal plan sooner to

accommodate higher traffic volumes anticipated by the detour.

6.4 I-394 Eastbound Closure Volume, average speed, and travel time data was collected for the weeks of August 3-14, 2015 from the

iMeasure system and was summarized in tables and charts.

• Eastbound iMeasure data reported up to a 50% increase in traffic volumes around the I-494 area

of the TH 55 corridor during the Mid-day period, and doubled in the Mid-Day period and

increased by 50% in the AM and PM periods on the east side of the TH 55 corridor.

• iMeasure reported up to 60% volume increases on northbound ramps from TH 100 onto TH 55

and southbound ramps from TH 55 onto TH 169.

• iMeasure reported slightly higher travel time data than baseline week travel time data. No

differences were found in the first and second weeks of the closure in terms of volumes and

travel times.

• iMeasure reported a drop in Arterial LOS in the westbound direction on Segments 2 and 3 from

LOS C to LOS E/F.

• Travel times were collected during the AM and PM peak periods. Seven runs were conducted in

each direction. The field collected travel times fell within the ranges reported by iMeasure,

verifying the accuracy of system.



10 Alliant 114-0136.0

6.5 Performance Measure Comparison The iMeasure system was utilized to develop travel time and travel speed estimations for the peak

periods. iMeasure allows the user to configure how many travel time “probe” vehicles are used to

estimate performance measures. The probe vehicle represents a specific vehicle leaving the first

signalized intersection in the system at a given time. More probe vehicles provide better coverage of

potential delays and variations in travel times. However, a large number of probe vehicles results in

slower performance of the iMeasure system and requires more data manipulation. For this project, one

probe vehicle for every 50 actual vehicles was found to provide the desired information. Manual travel

times were also conducted by Alliant staff to verify the performance of the iMeasure system, and to

provide more information during the two larger construction events caused by closures on I-394. The

following tables provide a summary of this information:

• Table 6.5.1 – Baseline Travel Times

• Table 6.5.2 – Baseline Arterial Level of Service

• Table 6.5.3 – Travel Times during Westbound I-394 Lane Closure

• Table 6.5.4 – Arterial Level of Service during Wesbound I-394 Lane Closure

• Table 6.5.5 – Travel Times during Eastbound I-394 Lane Closure

• Table 6.5.6 – Travel Times during Eastbound I-394 Lane Closure

A summary of the travel time information is included in the following bullets:

• Baseline travel times on the corridor range from 19-26 minutes.

• During the Westbound I-394 Lane Closure:

o Travel Times -

� AM Peak - iMeasure reported a range of travel times from 20-27 minutes. All manual

travel time runs fell within this range, confirming accuracy.

� PM Peak - iMeasure reported a range of travel times from 21-26 minutes, basically no

change from the baseline. Manually collected travel times – general range of 28-37

minutes, much higher than reported by iMeasure. The manually collected travel times

indicates an 11 minute increase in delay, which did not reach the criteria for enhanced

mitigation measures of 15 minutes.

o Arterial Level of Service -

� AM Peak – iMeasure reported little to no change in arterial LOS. This was confirmed by

field data.

� PM Peak – iMeasure reported no change in arterial LOS in either direction. However,

field data indicates that overall performance on the corridor dropped from LOS C to LOS

D. Segments 2 and 3 dropped to LOS F.

• During the Eastbound I-394 Lane Closure:

o Travel Times -

� AM Peak - iMeasure reported a range of travel times from 20-32 minutes. All manual

travel time runs fell within this range, confirming accuracy.

� PM Peak - iMeasure reported a range of travel times from 21-39 minutes. All manually

collected travel time runs fell into this range. The increased delay over baseline was 13

minutes, which did not reach the criteria for enhanced mitigation measures of 15

minutes.

o Arterial Level of Service -

� AM Peak – iMeasure reported a drop in performance from LOS C to LOS F in Segment 2.

This was confirmed by field data.

� PM Peak – iMeasure reported a drop in overall WB corridor performance from LOS C to

LOS D. For Segments 2 and 3, performance dropped to LOS F. This was confirmed by

field data.



11 Alliant 114-0136.0

Table 6.5.1

Baseline Travel Times

Notes: Low Range and High Range based on 15th and 85th percentile data

Data Sampling Parameters: Average of every 100th vehicle within time period

Days Sampled: Baseline week, Wednesday 4/1/15 thru Thursday 4/2/15



12 Alliant 114-0136.0

Table 6.5.2

Baseline Travel Speeds

Notes: Average Speed is calculated based on Travel Time Data

Low Range and High Range based on 15th and 85th percentile data

Data Sampling Parameters: Average of every 100th vehicle within time period

Days Sampled: Baseline week, Wednesday 4/1/15 thru Thursday 4/2/15



13 Alliant 114-0136.0

Table 6.3.3

Travel Times during Westbound I-394 Closure

Notes: Field travel time data was collected during July 14th thru July 16th, 2015 and July 23, 2015

Data was unavailable for Segment 1 Westbound, baselines were used to estimate Segment 1 Westbound ranges

Low High 07:25 07:26 08:18 08:18 - Low High 04:31 04:34 04:35 04:39 05:37 05:40 05:47

1 TH-55: Arrowhead Drive to I-494 West Ramp 9:21 10:49 11:04 10:19 07:50 10:12 - 9:05 11:03 08:33 11:04 10:17 08:53 08:39 10:00 08:27

2 TH-55: I-494 West Ramp to Revere Lane 4:39 5:53 05:27 03:37 05:20 05:00 - 5:23 6:53 07:26 08:54 04:46 09:16 04:31 05:45 04:36

3 TH-55: Revere Lane to TH-100 4:43 5:39 04:21 05:29 06:05 05:09 - 5:03 6:21 07:58 08:35 05:01 22:05 05:26 04:51 03:48

4 TH-55: TH-100 to Theodore Wirth Parkway 1:43 2:34 01:18 01:16 01:55 01:25 - 1:42 2:07 01:16 01:21 01:15 01:22 01:14 01:14 00:00

TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:27 24:57 22:10 20:41 21:10 21:46 - 21:14 26:26 25:13 29:54 21:19 41:36 19:50 21:50 16:51

Low High 07:00 07:00 07:48 07:49 08:41 Low High 04:00 04:00 04:00 04:00 04:58 04:59 05:05

4 TH-55: Theodore Wirth Parkway to TH-100 2:11 2:41 01:22 02:03 02:36 02:19 01:33 1:57 3:10 02:00 02:05 05:31 02:17 02:31 02:12 02:40

3 TH-55: TH-100 to Revere Lane 5:13 6:38 05:13 05:20 07:39 07:39 05:09 5:11 6:23 06:03 06:14 08:16 03:50 11:07 09:29 09:58

2 TH-55: Revere Lane to I-494 West Ramp 5:31 6:58 04:48 04:52 05:24 05:17 06:20 5:14 6:09 12:11 13:19 10:12 07:09 13:05 15:22 16:59

1 TH-55: I-494 West Ramp to Arrowhead Drive 9:08 10:39 10:34 10:16 09:59 09:48 08:26 9:12 10:09 08:03 09:28 09:09 08:36 09:18 09:52 09:38

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 22:04 26:57 21:57 22:31 25:38 25:03 21:28 21:35 25:52 28:17 31:06 33:08 21:52 36:01 36:55 39:15

Field Run (Start Time)

Segment Westbound

AM Peak PM Peak


Segment Eastbound

AM Peak PM Peak

iMeasure Range

iMeasure Range iMeasure Range

iMeasure RangeField Run (Start Time)




14 Alliant 114-0136.0

Table 6.3.4

Arterial Level of Service during Westbound I-394 Closure

NOTES: Vehicle sampling was for ever 50th vehicle over one-hour peak period

Baseline data was repulled for every 50th vehicle over one-hour period (was reported as every

100th vehicle in Baseline Memo)

Baseline data was pulled only for Wednesday, April 1st and Thursday, April 2nd

Data was unavailable for Segment 1 Westbound, Baseline values were utilized

Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change

1 TH-55: Arrowhead Drive to I-494 West Ramp 31,638 55 35.3 33.1 -6% 41.1 38.3 -7% 33.4 32.4 -3% 37.4 39.4 6%

2 TH-55: I-494 West Ramp to Revere Lane 16,270 55 31.3 31.3 0% 43.1 39.5 -8% 26.6 26.7 1% 34.5 34.2 -1%

3 TH-55: Revere Lane to TH-100 16,266 55 32.5 32.6 0% 39.9 39.0 -2% 30.0 29.0 -4% 41.4 36.5 -12%

4 TH-55: TH-100 to Theodore Wirth Parkway 5,389 50 28.2 23.7 -16% 38.4 35.5 -8% 28.9 28.7 -1% 36.5 35.7 -2%

TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69,563 55 33.0 31.6 -4% 41.1 38.6 -6% 30.4 29.8 -2% 37.4 37.1 -1%


4 TH-55: Theodore Wirth Parkway to TH-100 5,389 50 23.1 22.7 -2% 29.7 27.8 -6% 19.6 19.2 -2% 32.0 31.2 -3%

3 TH-55: TH-100 to Revere Lane 16,266 55 29.1 27.7 -5% 37.8 35.3 -7% 29.6 28.9 -2% 40.9 35.5 -13%

2 TH-55: Revere Lane to I-494 West Ramp 16,270 55 28.5 26.4 -7% 33.9 33.4 -2% 29.1 29.9 3% 33.0 35.2 7%

1 TH-55: I-494 West Ramp to Arrowhead Drive 31,638 55 33.4 33.4 N/A 39.6 39.6 N/A 34.7 34.7 N/A 39.0 39.0 N/A

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69,563 55 30.1 29.6 N/A 36.8 36.2 N/A 30.3 31.0 N/A 37.2 36.7 N/A

Low Range Speed High Range Speed Low Range Speed High Range Speed

AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM


AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM

Distance

(ft)EastboundSegment

Base FFS

(mph)

Distance

(ft)WestboundSegment

Base FFS

(mph)



15 Alliant 114-0136.0

Table 6.4.5

Travel Times During Eastbound I-394 Closure

WEEK OF 8/03/15

WEEK OF 8/10/15


Data Sampling Parameters: Average of every 50th vehicle within a one-hour time period


Table 6.4.6

Low High 07:26 07:26 08:18 08:18 - Low High 04:27 04:43 05:22 - - - -

1 TH-55: Arrowhead Drive to I-494 West Ramp 9:19 14:41 09:16 11:45 09:21 10:07 - 9:48 12:40 09:53 09:10 09:04 - - - -

2 TH-55: I-494 West Ramp to Revere Lane 4:37 6:21 04:45 03:17 04:15 04:52 - 5:21 6:52 05:04 05:03 05:12 - - - -

3 TH-55: Revere Lane to TH-100 4:36 5:35 05:59 03:20 07:08 05:13 - 4:31 5:22 05:53 06:04 08:42 - - - -

4 TH-55: TH-100 to Theodore Wirth Parkway 1:42 2:30 03:09 02:35 03:20 02:39 - 1:43 2:31 02:57 01:16 06:30 - - - -

TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:17 29:07 23:09 20:57 24:04 22:51 - 21:25 27:27 23:47 21:33 29:28 - - - -

Low High 07:00 07:00 07:51 07:51 08:43 Low High 04:00 04:00 04:54 05:06 - - -

4 TH-55: Theodore Wirth Parkway to TH-100 1:53 2:33 02:10 02:38 02:26 02:20 01:37 2:09 3:38 01:33 02:31 02:19 02:14 - - -

3 TH-55: TH-100 to Revere Lane 4:57 6:01 05:31 05:30 06:10 04:47 05:14 4:55 12:23 05:10 04:03 06:16 09:26 - - -

2 TH-55: Revere Lane to I-494 West Ramp 5:23 11:41 04:15 04:00 04:21 05:01 04:41 5:18 10:34 07:14 06:03 06:35 06:58 - - -

1 TH-55: I-494 West Ramp to Arrowhead Drive 9:03 10:43 09:36 09:56 09:54 10:13 07:42 9:11 10:20 08:38 13:05 07:46 09:47 - - -

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 21:16 30:59 21:32 22:04 22:51 22:21 19:14 21:34 36:56 22:35 25:42 22:56 28:25 - - -


Segment Westbound

AM Peak PM Peak


Segment Eastbound

AM Peak PM Peak

iMeasure Range




Low High 7:25 AM 07:26 8:20 AM 08:18 - Low High 4:24 PM 4:28 PM 5:20 PM 5:27 PM - - -

1 TH-55: Arrowhead Drive to I-494 West Ramp 9:35 11:00 13:11 12:01 07:46 07:37 - 9:18 11:17 09:59 09:45 08:58 10:57 - - -

2 TH-55: I-494 West Ramp to Revere Lane 4:33 5:56 04:11 04:20 05:31 05:25 - 5:28 6:58 08:30 05:02 04:52 04:53 - - -

3 TH-55: Revere Lane to TH-100 4:21 5:21 08:09 06:09 08:19 05:32 - 4:28 5:17 08:17 08:02 08:10 04:18 - - -

4 TH-55: TH-100 to Theodore Wirth Parkway 1:42 2:27 01:38 02:38 03:29 02:42 - 1:43 2:41 01:25 01:17 04:27 01:13 - - -

TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:13 24:44 27:09 25:08 25:05 21:16 - 20:58 26:14 28:11 24:06 26:27 21:21 - - -

Low High 7:00 AM 7:00 AM 7:54 AM 7:55 AM 8:45 AM Low High 4:00 PM 4:00 PM 4:54 PM 4:54 PM - - -

4 TH-55: Theodore Wirth Parkway to TH-100 1:52 2:35 02:20 01:43 02:27 02:11 01:19 2:05 2:57 01:47 02:21 02:17 02:42 - - -

3 TH-55: TH-100 to Revere Lane 4:43 5:52 05:23 05:16 05:07 06:07 05:00 4:52 19:41 02:47 05:02 04:09 06:36 - - -

2 TH-55: Revere Lane to I-494 West Ramp 5:18 12:35 04:01 03:55 04:58 04:15 04:41 5:12 5:59 06:40 07:05 07:11 09:40 - - -

1 TH-55: I-494 West Ramp to Arrowhead Drive 9:03 10:43 09:55 10:01 09:52 09:09 08:19 9:11 10:20 07:31 07:05 08:32 09:04 - - -

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 20:57 31:45 21:39 20:55 22:24 21:42 19:19 21:21 38:58 18:45 21:33 22:09 28:02 - - -


Segment Westbound

AM Peak PM Peak


Segment Eastbound

AM Peak PM Peak

iMeasure Range






16 Alliant 114-0136.0

Travel Times During Eastbound I-394 Closure

WEEK OF 8/03/15

WEEK OF 8/10/15


Data Sampling Parameters: Average of every 50th vehicle within a one-hour time period



1 TH-55: Arrowhead Drive to I-494 West Ramp 31,638 55 35.3 24.4 -31% 41.1 38.4 -7% 33.4 28.3 -15% 37.4 36.5 -2%

2 TH-55: I-494 West Ramp to Revere Lane 16,270 55 31.3 29.0 -7% 43.1 39.8 -8% 26.6 26.8 1% 34.5 34.4 0%

3 TH-55: Revere Lane to TH-100 16,266 55 32.5 33.0 2% 39.9 39.9 0% 30.0 34.3 14% 41.4 40.7 -2%


TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69,563 55 33.0 27.1 -18% 41.1 38.9 -5% 30.4 28.7 -6% 37.4 36.8 -2%


4 TH-55: Theodore Wirth Parkway to TH-100 5,389 50 23.1 23.9 4% 29.7 32.4 9% 19.6 16.8 -14% 32.0 28.3 -12%

3 TH-55: TH-100 to Revere Lane 16,266 55 29.1 30.6 5% 37.8 37.2 -2% 29.6 14.9 -50% 40.9 37.4 -9%

2 TH-55: Revere Lane to I-494 West Ramp 16,270 55 28.5 15.8 -45% 33.9 34.2 1% 29.1 17.4 -40% 33.0 34.8 6%

1 TH-55: I-494 West Ramp to Arrowhead Drive 31,638 55 33.4 33.4 0% 39.6 39.6 0% 34.7 34.7 0% 39.0 39.0 0%

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69,563 55 30.1 27.9 -7% 36.8 37.2 1% 30.3 24.6 -19% 37.2 36.8 -1%


AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM


AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM

Distance


Base FFS

(mph)

Distance


Base FFS

(mph)


1 TH-55: Arrowhead Drive to I-494 West Ramp 31,638 55 35.3 32.6 -8% 41.1 37.4 -9% 33.4 31.7 -5% 37.4 38.5 3%

2 TH-55: I-494 West Ramp to Revere Lane 16,270 55 31.3 31.1 -1% 43.1 40.4 -6% 26.6 26.4 -1% 34.5 33.7 -2%

3 TH-55: Revere Lane to TH-100 16,266 55 32.5 34.4 6% 39.9 42.3 6% 30.0 34.9 16% 41.4 41.2 -1%


TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69,563 55 33.0 31.9 -3% 41.1 39.0 -5% 30.4 30.1 -1% 37.4 37.6 0%


4 TH-55: Theodore Wirth Parkway to TH-100 5,389 50 23.1 23.6 3% 29.7 32.5 9% 19.6 20.6 5% 32.0 29.2 -9%

3 TH-55: TH-100 to Revere Lane 16,266 55 29.1 31.4 8% 37.8 39.0 3% 29.6 9.4 -68% 40.9 37.8 -8%

2 TH-55: Revere Lane to I-494 West Ramp 16,270 55 28.5 14.6 -49% 33.9 34.8 3% 29.1 30.8 6% 33.0 35.4 7%

1 TH-55: I-494 West Ramp to Arrowhead Drive 31,638 55 33.4 9:36 0% 39.6 14:24 0% 34.7 16:48 0% 39.0 0:00 0%

TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69,563 55 30.1 27.8 -8% 36.8 37.8 3% 30.3 26.8 -12% 37.2 37.1 0%


AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM


AM Peak Hour

7:30 AM-8:30 AM

PM Peak Hour

4:30 PM-5:30 PM

Distance


Base FFS

(mph)

Distance


Base FFS

(mph)



17 Alliant 114-0136.0

7 Lessons Learned

7.1 Success Stories This project was able to test how construction on a specific corridor would impact traffic conditions on a

parallel route. The two larger construction events on I-394 provided a significant change in traffic

conditions on TH 55. The data provided by the iMeasure system illustrated these impacts, and produced

expected changes in traffic volumes and traffic conditions.

iMeasure is a powerful tool that can document traffic volume levels and provide comparisons over

multiple time periods (days, weeks, months, years). The system’s travel time estimation algorithm is

accurate under most conditions. Manually collected travel time data verified the accuracy of the system

as part of this project.

Both travel times and arterial level of service (travel speed) are known performance measures that can

quantify corridor performance and impacts. In particular, arterial level of service can not only identify an

impact, but can also provide an understanding of the level of impact when compared to normal

conditions.

As part of this project, the group identified construction projects that may affect operations on TH 55.

Alliant signed up for email notifications, and periodically checked in with the MnDOT Construction

Project Manager for updates. This communication allowed the group to know about upcoming

construction activities that could result in impacts to traffic conditions.

This project used the iMeasure data as a “reactive” system, documenting conditions after the fact.

Under these circumstances, having data available within hours was perfectly acceptable. Traffic

conditions from the day before could be reviewed first thing the following morning.

The Highway 55 corridor proved to be capable of handling changes in traffic volumes within its normal

signal operations plan under most conditions. The iMeasure system provided validation that the corridor

was operating under acceptable parameters.

7.2 Problems Encountered The user interface in iMeasure could still use improvement. Data manipulation can be cumbersome for

larger corridors.

When conducting comparisons between time periods, the availability and consistency of data is

extremely important. Communications between traffic signals and the data server must be maintained

at all times. If communications is lost, data is not available to calculate travel times or to compare other

performance measures.

The corridor cannot include intersections controlled as all-way stops (either signed or if signals are on

red flash). The algorithms to calculate travel times, intersection delay, and queuing do not work under

this scenario.

Intersection Delay and Queueing were originally considered as potential performance measures.

However, both of these measures do not provide an understanding of the overall corridor performance.

While useful to identify “spot” issues, they do not give an overall evaluation of how the corridor is

operating.



18 Alliant 114-0136.0

Overall, the iMeasure systems appears to be accurate when measuring performance measures.

However, there were some instances (bad weather, incidents blocking lanes) that caused high levels of

queuing and congestion. Under these circumstances, iMeasure underestimated the level of congestion

(travel times, queuing, delays).

7.3 Best Practices Related to SMART-Signal Travel time estimation on signalized arterial corridors is more complex than on freeways. The signal

delay adds in variability under normal conditions. Travel times should be reported as a range. For this

project, the 15th and 85th percentile travel times were utilized as the low and high ends of the range.

Changes in the 85th percentile travel times should be used to indicate increased congestion, since

increases in the 15th percentile or average travel times might be just normal variations in traffic flow.

iMeasure uses “probe vehicles” to estimate travel times. The frequency of the probe vehicles is user

defined. For this project, we assumed that every 50th vehicle would act as a probe vehicle, which

provided us with the accuracy we were looking for when compared to field data.

The availability of data is necessary to develop and compare performance measures. iMeasure should

be checked frequently to confirm that all traffic signal equipment and communications are operating

properly. When problems are encountered, the issue should be rectified as soon as possible, or at least

noted so that the reason for missing data is understood.

On future projects, data from the iMeasure system could be used to modify the time-of-day signal

timing program to better address changes in traffic flows caused by construction. Under extreme

circumstances with long durations, this data could also be used to develop a new signal timing plan.

The system could be used to validate traffic complaints (both for corridors under construction and

“normal” corridors). When a complaint is received, information such as delay, queuing, and travel time

can be reviewed from the time period in question to determine if a problem existed.

7.4 Monitoring Work Zone Performance Measures on Future Projects Based on the experience of this project, the group discussed developing a methodology that could be

used on projects in the future. The steps below provide a high level summary of a process that could be

followed.

1. Prepare a Transportation Management Plan (TMP) to identify potential impacts and possible

mitigation measures that could be implemented prior to construction beginning. These

mitigation measures could include but are not limited to:

a. Changes in signal timing

b. Turn lane closures

c. Side-street access closures

d. Intersection closures

e. Signed detour routes

f. Time restrictions for work activities

2. As part of the TMP, performance measures should be identified to monitor potential impacts

during construction. For urban streets, arterial level of service is the recommended

performance measure. The indicator of congestion would be dependent on the performance of

the corridor prior to construction.

3. If the corridor is operating at LOS E/F under normal conditions, mitigation measures need to be

addressed during the TMP prior to construction. The corridor may not be capable of handling

additional traffic or lane restrictions, without physical changes. Measures could include:



19 Alliant 114-0136.0

i. More robust traffic control plan, including temporary pavement to maintain

lane capacity

ii. Side-street access closures

iii. Road closures and detours

iv. Allowing night-work only

4. During construction, the following criteria could be used to trigger increased mitigation

measures:

a. The LOS D/E boundary is typically considered the indicator of congestion for signalized

intersections and corridors in urban areas. Changes in performance that do not fall

below this boundary may not require mitigation.

b. A drop in corridor or segment performance to LOS E or LOS F indicates the need for

enhanced mitigation. Mitigation measures could include:

i. Changes to time-of-day signal timing program

ii. Creation of a new timing plan

iii. Lane closures

iv. Time restrictions for work activities

5. Communication is critical to proactively respond to congestion caused by work activities.

a. A thorough summary of all construction projects that could potentially impact the

subject corridor should be prepared. This list should include not only MnDOT projects,

but all agency projects. A contact list should be developed identifying the construction

manager and the project website. If available, the person that will be monitoring traffic

conditions should sign up for email notifications of upcoming construction activities.

Prior to construction beginning, major changes in traffic control should be identified,

along with the approximate timeline.

b. The signal operations group should be engaged early in the process (during the TMP) to

make them aware of the possible impacts to the corridor. In addition, other signal

operating agencies may need to be involved if construction will impact parallel

corridors.

6. Prior to construction beginning, the performance of the corridor should be measured to set the

baseline for the project. This may occur during the TMP process, but if not, it should happen

before construction begins. Performance could be measured manually by field studies, or using

a HRMS system such as SMART-SIGNAL

7. During the project, corridor operations should be monitored immediately following any changes

in traffic control or lane configurations.

8. For large events, potential mitigation measures should be discussed well in advance of the event

so that time is available to develop changes in signal timing and other measures.



20 Alliant 114-0136.0

8 APPENDIX

• Technical Memorandum No. 1 – Current Practices and Policies (12/21/14)

• MnDOT Work Zone Performance Measures Concept of Operations (04/09/16)

• MnDOT Work Zone Performance Measures System Requirements (04/09/16)

• Work Zone Memo No. 1 – March 2015 – Baseline Conditions

• Work Zone Memo No. 2 – April 2015 – Monthly Report

• Work Zone Memo No. 3 – May 2015 – Monthly Report

• Work Zone Memo No. 4 – June 2015 – Monthly Report

• Work Zone Memo No. 5 – July 2015 – I-394 Westbound Closure Report

• Work Zone Memo No. 6 – August 2015 – I-394 Eastbound Closure Report

• Work Zone Memo No. 7 – July 2015 – Monthly Report

• Work Zone Memo No. 8 – August 2015 – Monthly Report

estimating work zone performance measures on signalized arterial · pdf file ·...

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