01628900

Component

Although they are meant for pedestrians, pedestrian countdown signals (PCSs) give cues to drivers about the length of the remaining green phase, causing some to speed up to clear the intersection and avoid being stopped at the red light, or to slow down avoiding running a red light, when the timer approaches zero. Drivers of different age groups might receive the PCSs cues and act differently depending on their level of aggressiveness. This study evaluated the influence of PCSs on vehicle approach speed at signalized intersections as a function of driver age. Speeds of vehicles as they cross the stop bar when PCSs were operating were compared to when they were off. To understand the influence of PCSs when they start to count down compared to when the timer approaches to zero, the analysis of the study was divided into the first 20 seconds and the last 10 seconds of the green phase. The difference in observed mean speeds were tested at the 95% level of confidence. Additionally, the difference in vehicle mean speed between old and younger drivers was compared when PCSs were operating and when they were off. Mean speeds were observed to be higher when PCS timer were operating than when they were off. In addition, the average speeds during the first 20 seconds of green phase were lower than the mean speeds during the last 10 seconds of the green phase. The older drivers mean speed was significantly lower than the average speed of younger drivers.

This paper was sponsored by TRB committee AHB50 Standing Committee on Traffic Control Devices.

01618707

17-06518

English

17p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; Photos; References; Tables

Age; Aged drivers; Drivers; Signalized intersections; Speed

Aggressive driving; Countdown timers

Highways; Operations and Traffic Management; Safety and Human Factors

Transportation Research Board Annual Meeting 2017 Paper #17-06518

TRIS, TRB, ATRI

Dec 8 2016 12:39PM