ABSTRACT
Time to contact or time to impact (TTC), the time left just before the impact between two vehicles, can be specified by optic cues from optic flow. Lee (1976) proposed that the determination of time to contact or time to impact was directly from perception of tau, the source of optical information specifying time to contact or time to impact. Psychophysical experiments exposed that within certain temporal range time to contact or time to impact judgments were fairly accurate and one could directly employ the optical cue tau in daily life. Time to contact or time to impact values were overall underestimated and the underestimation bias increased as actual time to contact or time to impact continues to increase.
