Dilemma Zone Driver Behavior as a Function of Vehicle Type, Time of Day, and Platooning

Abstract

A comprehensive investigation of the influence of vehicle type on various aspects of dilemma zone driver behavior, including brake response time, deceleration rate, and red light running occurrence, was performed at six urban or suburban signalized intersections in Wisconsin. Driver behavior data were obtained for 1,275 vehicles that were between 2.0 and 6.5 s upstream of the intersection at the onset of the yellow interval. Each vehicular observation was classified into one of five vehicle type categories: motorcycle, car, light truck (pickup, SUV, van, minivan), single-unit truck (single-unit heavy truck, delivery truck, recreation vehicle, bus), and tractor trailer (multiunit heavy truck). Each observation was also classified by time of day and whether the subject vehicle was part of a platoon. Vehicle type had a statistically significant effect on deceleration rate and red light running occurrence but did not have an effect on brake response time. Deceleration rates were highest for cars and light trucks; single-unit trucks and tractor trailers showed the lowest deceleration rates. Tractor trailers were 3.6 times more likely and single-unit trucks were 2.5 times more likely to commit red light running compared with passenger vehicles. The rates of red light running for cars and light trucks were not substantially different from each other. Time of day (peak versus off-peak) had a statistically significant effect on both deceleration rate and occurrence of red light running. Deceleration rates were significantly higher during off-peak times. Red light running was 1.3 times more likely to occur during peak periods compared with off-peak periods. Platooning had no effect on any of the measures of effectiveness.