brandon signals council presentation

TRAFFIC SIGNAL COORDINATION

STUDY IN THE CITY OF BRANDON

Presentation to Brandon City Council

Monday, February 2, 2015 @ 7:00 p.m.

Brandon City Council Presentation | February 2, 2015

1) Introduction

2) Existing Conditions

3) Signal Timing 101

4) Signal Timing Recommendations

5) Post Optimization

6) Conclusions

7) Recommendations

8) Going Forward . . .

9) Questions?

AGENDA

http://www.google.ca/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fwww.durham.ca%2Fworks.asp%3Fnr%3D%2Fdepartments%2Fworks%2Froads%2Ftraffic%2Fcontrolsignals.htm&ei=uN3LVKaGHM_moASftYBw&bvm=bv.85076809,d.cGU&psig=AFQjCNGXMHi21HicJC4tWt5jtRFsiR6ftg&ust=1422733050146391


Introduction

• Existing signal network in Brandon is comprised of a

combination of MIT signals and City of Brandon signals

• MIT signal network operations were last reviewed in 2000

• City of Brandon has experienced significant growth in the

past 15 years and new signals have been added to the

network

• Joint study for MIT and the City of Brandon to review the

current signal network


Introduction

• Purpose of the study is to develop a model of the signal

network that can be used to recommend modifications to

improve the safety and efficiency of roadway corridors today

and in the future

• The focus of this project was to optimize operations for the

entire signal system, not individual intersections

• The model is the starting point to improve signal timing

operations in Brandon

• Changes have been made for the short-term, but the model can

be used to test long-term changes going forward


Introduction

• The study looked at signal operations on nine corridors:

1) 18th Street

2) PTH 1A / 1st Street

3) Victoria Avenue / PTH 1A / Victoria Avenue East

4) Richmond Avenue / Richmond Avenue East

5) Kirkcaldy Drive

6) Rosser Avenue

7) Princess Avenue

8) 26th Street

9) Park Avenue


Existing Conditions

• Site inspections performed at all signalized intersections

• Intersection traffic volumes and signal timings collected from

MIT and the City of Brandon

• Model of the signal network created using Synchro software

for 4 analysis periods (am, pm, noon, off-peak)

• Analysis of each intersection with existing signal timings

• Investigated locations identified by MIT and the City of

Brandon as having specific concerns

• Conducted travel time studies on each corridor to collect

information on travel times and delays


Signal Timing 101

• Signal timing is complex and requires many inputs, including

factors related to the road geometry, traffic volumes, speeds,

signal phases, driver and pedestrian characteristics, etc.

• Traffic volumes

• Link speed

• Saturated Flow Rate

• Lane Utilization Factor

• Percent Heavy Vehicles

• Minimum Initial Green

• Yellow Time

• All-Red Time

• Vehicle Extension

• Minimum Gap

• Recall Mode

• Storage Lane Length

• Detector Position

• Pedestrian Walking Speed

• Peak Hour Factor

• Critical Gap for Permitted Left

Turn

• Follow-up Time for Permitted

Left Turn

• Stop Threshold Speed

• Critical Merge Gap

• Walk Time

• Flash Don’t Walk Time

• Turning Speed


Signal Timing 101

• In order to coordinate intersections in close proximity, the

same cycle length must be used

• Priority must be given to the movements with highest traffic

volumes, typically the through movements

• Signal timing and coordination is an iterative process of

finding the optimal cycle length for one corridor, and checking

to see if that cycle length works for crossing corridors

• Many corridors cross, which means prioritizing between

corridors and possibly increased delay on more minor streets

• Changes made to timings at one intersection affect

operations at surrounding intersections and along the corridor


Signal Timing 101

• Example signal timing diagram with 90 sec cycle length and

protected left turn phases:

• Total length (time) of the cycle is set

• Yellow (amber) time and all red time is set

• Pedestrian crossing time is set and impacts minimum green

• To add green time to one direction requires taking away green

time from another direction


Signal Timing Recommendations

• Signal timings were optimized using the model

• Adjacent MIT and City of Brandon signals cannot be coordinated

• Some of the corridors cross each other, which creates the need

to prioritize corridors with higher demand

• Iterative process using trial and error to balance the needs of

different corridors

• Recommended timings provide the best level of service for the

overall signal system

• The majority of intersections forecast to operate at the same or

better level of service with reduced delay

• Some intersections warranted additional improvements, such

as the addition of detectors or geometric changes


Post Optimization

• MIT implemented recommendations at provincially owned

intersections in April 2014

• Most timing errors made during implementation were found and

corrected within weeks

• Additional timing errors noticed during post-optimization travel

time studies and during analysis of results

• City updated signals in November 2014

• City of Brandon currently uses one signal timing plan

• New offsets were provided for the existing plans but full

recommended improvements were not implemented


• Second round of travel time studies conducted on each

corridor to collect information on travel times and delays

• Minor improvements on most corridors

• Some additional timing changes recommended after issues

noted during travel time runs

Post Optimization


• Complete model of the Brandon signal network was created

and will be provided to both MIT and the City of Brandon

following completion of the study

• The results of the model are directly linked to the data that is

used

• Changes in traffic volumes, turning movements and speed

information can each or collectively have a major impact on

the signal timing recommendations

• Good input data is critical to how well the model performs

Conclusions


• Model should be updated on an ongoing basis (every 3 years

recommended) in order to remain valid for current conditions

• Includes if and when there are major changes to the network,

like if new signals added to system or signalized intersection is

removed from system

• New traffic counts should be input into model

• Traffic counts should be conducted on continuous basis to

obtain better estimates of actual traffic volumes and turning

movements at intersections

• Regular counting program for both MIT signals and City signals

would improve accuracy of model and assist with future

optimization recommendations

Recommendations


• Revised coordination speeds should be input into model

• Speed studies should be conducted to determine appropriate

coordination speeds for each corridor

• All signal timing changes made to system should be verified

by field observations following implementation

• The long-term recommendations should be implemented

when funding is available

Recommendations


• MIT and the City of Brandon will each have a complete model

of the signal network in Brandon for their future use

• The model can be used to:

• Recommend options to address concerns at specific

intersection locations

• Investigate impacts of changes to the signal network

• Review signal timings whenever major changes occur on a

specific corridor

• Update signal timings for the overall system on a regular basis

to reflect current operating conditions

Going Forward . . .


THANK YOU

QUESTIONS?

brandon signals council presentation

Documents