Drivers' Steering Behavior during Traffic Events: A Case of Perceptual Tropism?

Abstract

Seventy-five drivers participated in test runs, driving a total of 1500 km. Mean value and 1 standard deviation of steering wheel angle were plotted for several traffic events from 10 s before the event until 10 s after. Two seconds before meeting an oncoming car, there was a 1° shift in steering wheel angle to the left, thereby moving toward the oncoming car. The peak value was obtained at the instant when the oncoming car passed. The original steering wheel position was regained 2 s after the meeting. The behavior was more pronounced on narrow roads than on wide roads, and it was unaffected by driving experience. The behavior is explained by the perceptual significance of the oncoming car and, in analogy with tropistic behavior noted in lower organisms, the phenomenon is called perceptual tropism. The findings introduce a new dimension to analyses of steering behavior. More important, the obtained results suggest that there are interactions between visual and motor behavior.