An Empirical Investigation of the Influence of Perception of Time-To-Collision on Gap Control in Automobile Driving

Optical looming has been proposed as a potentially important cue for the perception of time-to-collision (TTC) in the control of locomotion. In this paper, an investigation is reported on how manipulation of the optical looming cue can influence the perception of TTC, and thereby braking behaviour, for automobile driving in a low fidelity simulator. Eleven participants were instructed to follow a leading vehicle (LV) and appropriately respond to the braking events of the LV, which occurred randomly at different deceleration rates. For some braking events, during braking of the LV, size of the LV was expanded without subjects being aware of it. Results showed that subjects braked sooner when confronting an expanding LV compared to a constant-size LV. The experiment supports the theory that drivers use TTC information derived from optic looming to control braking. Potential application of the results to possibly reduce occurrences of rear-end collisions in real automobile driving is also discussed.