The research presented in this paper characterizes driver stopping behavior at the onset of a yellow-phase on high-speed signalized intersection approaches using controlled field data gathered from 60 test subjects using an in-vehicle Differential Global Positioning System (DGPS). A total of 745 data records were available for analysis for all drivers who stopped at the onset of the yellow-phase, ranging from a minimum time to the stop bar(TTS) of 1.34 s to a maximum of 6.19 s. Statistical analyses were used toinvestigate the effects of the time to stop bar, grade (uphill and downhill), age (under 40-years-old, 40 to 59-years-old, and 60 years of age or older), and gender on seven dependent measures of driver performance including perception time, reaction time, perception-reaction time, braking time, stopping time, and stopping accuracy. The study demonstrates that driverperception time is not impacted by TTS while reaction time is dependent on TTS, roadway grade, and driver age. Younger drivers have longer reactiontimes in comparison to the older group but they are able to stop over a shorter period of time as they typically apply more aggressive braking rates. A lower perception-reaction time was found for drivers who have their foot lifted off the accelerator at the onset of the yellow-phase. Male drivers show slightly higher braking times when compared to female drivers with no significant differences between male and female drivers. Furthermore,the results demonstrate that drivers who try to stop at short TTSs are more likely to stop downstream of the stop line and that older drivers are significantly more accurate when they stopped compared to other age groups.
Samenvatting