An Assessment of the Operational Benefits of Countdown Pedestrian Signals John R. Engle

transcript

An Assessment of the Operational Benefits of

Countdown Pedestrian Signals

John R. EngleGhassan Abu-Lebdeh

Thomas Maleck

Department of Civil and Environmental EngineeringMichigan State University

Project Description

• 16 Intersections along MDOT State Trunklines within the State of Michigan

• 20 Hours of Data for Before and After Conditions

• Survey of Pedestrians

What is a Countdown Pedestrian Signal (CPS)?

• After implementation, majority of peds in the crosswalk (when Solid Don’t Walk phase began) tended to be closer to curb.

• Being closer to their destination, the peds were able to leave the roadway quicker after the flashing don’t walk phase ended.

• People overwhelmingly liked them.

What was discovered:

• There are significant exceptions to the generalizations made previously

• There were a significant number of intersections in which this did not occur

• Much of this variance could potentially be attributed to social/economic characteristics of the pedestrians

What was discovered:

The 16 Intersections were broken down into three groups for analysis.

• Michigan @ Larch - Lansing

• Saginaw @ Capitol - Lansing

• Saginaw @ Pennsylvania - Lansing

• Michigan @ Rose - Kalamazoo

• Bridge @ Jefferson - Grand Ledge

• Beach @ 5th - Flint

Group A:

Group A Findings

• ‘Normal’ geometric layouts with peds exhibiting ‘usual’ behavior

• After CPS, a small increase in volume of peds who cleared before solid don’t walk (SDW) phase

• After CPS, minor decrease in the percentage of pedestrians crossing on the SDW phase

• In five of the six locations of Group A, after CPS implementation a larger percentage of peds began crossing during flashing don’t walk (FDW) phase

• With CPS, if peds were ‘caught’ in the intersection when FDW phase ended, they tended to be much closer to their destination curb than before

2.7%10.1%

2.8%12.3%

0.0%10.0%20.0%30.0%40.0%50.0%60.0%70.0%80.0%90.0%

Cleared before Solid Don’tWalk

Didn’t clear before SolidDon’t Walk

Started during FlashingDon’t Walk

Crossing on Solid Don’tWalk

Before Ped Countdown Signal

After Ped Countdown Signal

Saginaw/Capital Location - Lansing

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Lanes to Cross when Solid Dont Walk Signal Appears

Saginaw/Capital Location - Lansing

• Gratiot @ Linhurst - Detroit

• Gratiot @ Hickory - Detroit

• Gratiot @ Outer - Detroit

• Gratiot @ Filbert - Detroit

• Dexter @ Washington - Ionia

• Genesee @ Washington - Saginaw

Group B:

• Locations in distressed, lower income neighborhoods

• Number of pedestrians that exhibited unusual walking behaviors was significantly higher than at other locations

Group B Findings

• For five of the six locations, percentage of peds who cleared before the solid don’t walk increased after CPS

• Percentage of peds crossing on SDW also decreased for five of the six locations

Group B Findings

13.3%20.0%

17.1%11.4%

Cleared before Solid Don’tWalk

Didn’t clear before SolidDon’t Walk

Started during FlashingDon’t Walk

Crossing on Solid Don’tWalk

Gratiot/Outer Location - Detroit

10.0%20.0%

40.0%50.0%

70.0%80.0%

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5

Gratiot/Outer Location - Detroit

• Mission @ Bellows - Mt Pleasant

• Michigan @ Ann Arbor - Saline

• Wyoming @ 8 Mile - Detroit

• VanDyke @ 10 Mile - Centerline

Group C

• “Miscellaneous” group

• No consistency between intersections

• Four intersections, locations w/ certain unique geometric layout, traffic flow, or pedestrian behavior may have resulted in different behavior problems

Group C Findings

• Near CMU campus• Majority of peds were college students, who

displayed more aggressive walking behaviors• Often would use countdown clock from another

approach to decide• This may explain the higher percentage of peds

crossing on solid don’t walk after the CPS

Case Example: Mt Pleasant

• Demographics similar Group A• Unique geometric feature: very wide highway

width of VanDyke with no median (~108 ft)• After CPS a greater % cleared before the solid

don’t walk• Little change on bringing peds closer to curb• Possible, CPS encouraged peds to walk faster

compared to an unusually long flashing don’t walk phase

Case Example: Centerline

• Near a school• Majority of peds middle school and elementary

school children who crossed 8 Mile Road • Majority of peds were unable to clear the

intersection in one phase• Resorted to waiting on a median island before

completing their crossing

Case Example: Detroit/8Mile

0.5 1 1.5 2 2.5 Island 3.5 4 4.5 5 5.5

Wyoming/8Mile Location - Detroit

• Exception to majority of behaviors

• Located in a exurb of Ann Arbor

• Majority of peds high income demographic.

• Unclear why after CPS a lower % of peds cleared before solid don’t walk, or why

Case Example: Detroit/8Mile

Survey Results

What do you think of the countdown clock on the pedestrian signal?

81.48%

3.70%14.81%

0.00%10.00%20.00%30.00%40.00%50.00%60.00%70.00%80.00%90.00%

I like It I don’t like it I don’t know

Survey ResultsWhat does the countdown clock mean?

74.07%

7.41% 11.11% 7.41%

20.00%

40.00%

60.00%

80.00%

You must beacross the

intersection bythe time the

clock reacheszero

You must begincrossing the

intersection bythe time the

clock reacheszero

When the clockreaches zero,the walk signwill appear forthat crosswalk

I don’t know

Summary

• Impact was mostly positive– There appear to be some exceptions– Non-engineering factors important at some

• More analysis needed– Statistical– Qualitative

• Relevant finding to start develop guidelines

Questions?

An Assessment of the Operational Benefits of Countdown Pedestrian Signals John R. Engle

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