Driver Stopping Behavior on High-Speed Signalized Intersection Approaches

The research presented in this paper characterizes driver stopping behavior at the onset of a yellow phase on high-speed signalized-intersection approaches through the use of controlled field data gathered from 60 test subjects by means of an in-vehicle differential global positioning system. A total of 745 data records were available for analysis of all drivers who stopped at the onset of the yellow phase. These ranged from a minimum time to the stop bar (TTS) of 1.34 s to a maximum of 6.19 s. Statistical analyses were used to investigate the effects of the TTS bar, grade (uphill and downhill), age (younger than 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 demonstrated that driver perception time was not affected by TTS, while reaction time was dependent on TTS, roadway grade, and driver age. Younger drivers had longer reaction times than the older group, but they were able to stop over a shorter period of time, as they typically applied more aggressive braking rates. A lower perception–reaction time was found for drivers who had their foot lifted off the accelerator at the onset of the yellow phase. Male drivers showed slightly higher braking times than female drivers, with no significant differences between male and female drivers. Furthermore, the results demonstrated that drivers who tried to stop in short TTSs were more likely to stop downstream of the stop line and that older drivers were significantly more accurate when they stopped than other age groups.