an assessment of the operational benefits of countdown pedestrian signals john r. engle
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An Assessment of the Operational Benefits of Countdown Pedestrian Signals John R. Engle Ghassan Abu-Lebdeh Thomas Maleck Department of Civil and Environmental Engineering Michigan State University. Project Description. - PowerPoint PPT PresentationTRANSCRIPT
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
2
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
3
What is a Countdown Pedestrian Signal (CPS)?
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• 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:
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• 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:
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The 16 Intersections were broken down into three groups for analysis.
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• Michigan @ Larch - Lansing
• Saginaw @ Capitol - Lansing
• Saginaw @ Pennsylvania - Lansing
• Michigan @ Rose - Kalamazoo
• Bridge @ Jefferson - Grand Ledge
• Beach @ 5th - Flint
Group A:
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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
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• 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
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75.8%
2.7%10.1%
21.5%
76.5%
2.8%12.3%
20.7%
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
Perc
enta
ge o
f Tot
al P
edes
trian
s
Before Ped Countdown Signal
After Ped Countdown Signal
Saginaw/Capital Location - Lansing
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0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Lanes to Cross when Solid Dont Walk Signal Appears
Per
cen
tag
e o
f Ped
estr
ian
s
Before Ped Countdown Signal
After Ped Countdown Signal
Saginaw/Capital Location - Lansing
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• Gratiot @ Linhurst - Detroit
• Gratiot @ Hickory - Detroit
• Gratiot @ Outer - Detroit
• Gratiot @ Filbert - Detroit
• Dexter @ Washington - Ionia
• Genesee @ Washington - Saginaw
Group B:
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• Locations in distressed, lower income neighborhoods
• Number of pedestrians that exhibited unusual walking behaviors was significantly higher than at other locations
Group B Findings
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• 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
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43.3%
13.3%20.0%
43.3%
58.2%
17.1%11.4%
24.7%
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
Cleared before Solid Don’tWalk
Didn’t clear before SolidDon’t Walk
Started during FlashingDon’t Walk
Crossing on Solid Don’tWalk
Perc
enta
ge o
f Tot
al P
edes
trian
s
Before Ped Countdown Signal
After Ped Countdown Signal
Gratiot/Outer Location - Detroit
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0.0%
10.0%20.0%
30.0%
40.0%50.0%
60.0%
70.0%80.0%
90.0%
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
Lanes to Cross when Solid Dont Walk Signal Appears
Per
cent
age
of P
edes
tria
ns
Before Ped Countdown Signal
After Ped Countdown Signal
Gratiot/Outer Location - Detroit
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• Mission @ Bellows - Mt Pleasant
• Michigan @ Ann Arbor - Saline
• Wyoming @ 8 Mile - Detroit
• VanDyke @ 10 Mile - Centerline
Group C
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• “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
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• 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
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• 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
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• 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
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0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
0.5 1 1.5 2 2.5 Island 3.5 4 4.5 5 5.5
Lanes to Cross when Solid Dont Walk Signal Appears
Per
cen
tag
e o
f Ped
estr
ian
s
Before Ped Countdown Signal
After Ped Countdown Signal
Wyoming/8Mile Location - Detroit
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• 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
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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
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Survey ResultsWhat does the countdown clock mean?
74.07%
7.41% 11.11% 7.41%
0.00%
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
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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
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Questions?