Driver steering reaction time to abrupt-onset crosswinds, as measured in a moving-base driving simulator.

Abstract

A moving-base driving simulator was used in three experiments involving driver reaction time (RT) to simulated crosswind disturbances. Analyses were conducted on driver steering reaction time (RT) to the disturbances. Experiment 1 revealed that RT was significantly shorter when physical-motion cues were present. A second variable, vehicle yaw rate rise time, showed no effect. In Experiment 2, design parameters influencing aerodynamic behavior of a vehicle were adjusted. RT increased as the vehicle center of pressure (point of crosslvind application) moved rearward (rom the (ront axle. However, rearward movement of the center of pressure also produced less disturbance of the vehicle itself Changes in understeer and steering sensitivity yielded no significant effect. In Experiment 3, both uninitiated drivers and drivers with time on task were examined. Neither the first exposure to a step gust nor driving time up to 150 mirl caused significant changes in RT when perfurmance was compared with that of practiced, fresh drivers. Interexperiment comparisons using crosswind amplitude and shape as independent variables demonstrated that the amplitude and rise time of the crosswinds were critical determinants of steering RT.