Driver Approach Speed and Its Impact on Driver Yielding to Pedestrian Behavior at Unsignalized Crosswalks

Abstract

This study evaluated the effect of motor vehicle speed on yielding rates to pedestrians in marked crosswalks. The experimental design was to measure the 85th percentile speed at nine locations and then to run to 100 tests at each of nine locations to check for motorist yielding at various speeds. The 85th percentile speed was calculated, and the AASHTO guidelines were used to calculate stopping sight distance. Then a cone was placed at the calculated stopping sight distance away from the marked crosswalk, and a pedestrian was asked to step into the street to test yielding behavior in a staged experiment. Data were collected on site and recorded for analysis. Overall, there was an inverse correlation: the higher the motor vehicle speed was, the lower the yield rate was. Of the eight two-lane roadways, the range was from a 75% yield rate for the 20 mph street to a 17% yield rate for the 37 mph street, a significantly lower yield rate. The one street that was four lanes wide had only a 9% yield rate. The results unequivocally showed that speed was the major factor in the changing yield rates. The strong correlation pointed to a likelihood of low yield rates regionally on high-speed roadways, information that may prove useful for agencies looking to develop a pedestrian-friendly environment.