Nebraska Department of Roads Conference 2012 Presented by Dr. Anuj Sharma, University of Nebraska-Lincoln

1. Effect of Pedestrian Countdown Timer on
Safety and Efficiency of Operations at
Signalized Intersections
Anuj Sharma, Ph.D.
Department of Civil Engineering
University of Nebraska-Lincoln

2. Objective of Research
• Evaluate the effects a countdown timer has
on safety and efficiency of operations at an
intersection and public view.

3. Past Literature: Pedestrians

4. Intersection Selection
• Two intersections chosen:
– S 17th St & G St (Pedestrian and Drivers)
• Northbound Approach
• Speed Limit 35 mph
– N 27th St & Cornhusker Highway (Drivers)
• Eastbound Approach
• Speed Limit 40 mph

5. Pedestrian Data

6. Driver Data

7. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed
• Probability of Stopping
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

8. Pedestrian Analysis (Only for
17th and G)
• 861 pedestrians before installation (April-March)
(Mean temp 56 F)
• 495 pedestrians after installation (Oct-end) (Mean
temp 56 F)
• Clear weather conditions

9. Compliance Results

11. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed
• Probability of Stopping
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

12. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed
• Probability of Stopping
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

13. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

15. Probability of Stopping at
27th and Cornhusker

16. Important Results
• RLR (17 & G):
– Before 10 of 429 vehicles ran the red light
(2.3%)
– After 3 of 422 vehicles ran the red light (0.7%)
• RLR (27 & Cornhusker):
– Before 7 of 525 vehicles ran the red light
(1.3%)
– After 8 of 482 vehicles ran the red light (1.6%)

17. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping: 17th and G
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

18. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping: 17th and G
27th and Cornhusker
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

19. 17th and G

20. 27th and Cornhusker

21. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping: 17th and G
27th and Cornhusker
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

22. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping: 17th and G
27th and Cornhusker
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

23. Queue Discharge: 27th and
Cornhusker

24. Performance Measures
• Pedestrian Compliance
• Pedestrian Walking Speed (4.7 ft/s 4.9 ft/s)
• Probability of Stopping: 17th and G
27th and Cornhusker
• Speed Gain at Stopbar during Yellow Phase
• Change in Queue Discharge

25. Survey: NASIS
• 2,032 responses collected

26. Pedestrian Impact (2032)

27. Driver Impact (2018)

28. Conclusions
• The empirical evidence in this study support the
use of PCT and have found no negative impact at
the two sites.
• The impact of PCT on the two sites were different
implying the interaction of site-specific parameter
can influence the results.

30. CREDITS
Dr. Anuj Sharma, Ph.D.
Assistant Professor
Department of Civil Engineering
University of Nebraska-Lincoln
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