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Do Pedestrian Countdown Signals Influence Vehicle Speeds? Nambisan, Shashi S ; Karkee, Ganesh J

By: Contributor(s): Series: Transportation Research Record: Journal of the Transportation Research Board ; 2149Publication details: Washington DC Transportation Research Board, 2010Description: s. 70-76ISBN:
  • 9780309142809
Subject(s): Bibl.nr: VTI P8167:2149Location: TRBAbstract: The effects of pedestrian countdown signals on speeds of approaching vehicles as a function of the distance of the vehicle upstream of the intersection and the signal display are reported here. The analyses used mean speeds of vehicles on two segments immediately upstream of the stop bar and also during different indications of the pedestrian signal head (pedestrian "Walk" and pedestrian flashing "Don't Walk" signal with the time remaining in seconds to cross the street for the following intervals: greater than 15 s, 15 s to 10 s, 10 s to 5 s, and less than 5 s). Appropriate tests were performed to determine the statistical significance of the differences in observed mean speeds for each of these scenarios. Vehicle speeds were greater on the segment closer to the intersection than on the segment farther away. The speeds were also greater during the pedestrian countdown timer and flashing Don't Walk" displays on the pedestrian signal head than when the pedestrian "Walk" signal and the countdown timer were displayed. All results were statistically significant at a 95% level of confidence except one, which had a 93% level of confidence. Results do not indicate that speeds are affected by the actual numeric displays on the countdown timer.
Item type: Reports, conferences, monographs
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Statens väg- och transportforskningsinstitut Available

The effects of pedestrian countdown signals on speeds of approaching vehicles as a function of the distance of the vehicle upstream of the intersection and the signal display are reported here. The analyses used mean speeds of vehicles on two segments immediately upstream of the stop bar and also during different indications of the pedestrian signal head (pedestrian "Walk" and pedestrian flashing "Don't Walk" signal with the time remaining in seconds to cross the street for the following intervals: greater than 15 s, 15 s to 10 s, 10 s to 5 s, and less than 5 s). Appropriate tests were performed to determine the statistical significance of the differences in observed mean speeds for each of these scenarios. Vehicle speeds were greater on the segment closer to the intersection than on the segment farther away. The speeds were also greater during the pedestrian countdown timer and flashing Don't Walk" displays on the pedestrian signal head than when the pedestrian "Walk" signal and the countdown timer were displayed. All results were statistically significant at a 95% level of confidence except one, which had a 93% level of confidence. Results do not indicate that speeds are affected by the actual numeric displays on the countdown timer.