Time to collision (TTC)

Current consensus

Time to collision means the time before a collision happens between involved vehicles-objects-subjects if their speeds would not change and taking into account their paths.

Explanation

For pure longitudinal situations with constant speeds, unless differently specified in the text, the TTC is obtained by dividing the longitudinal distance (in the direction of travel of the subject vehicle) between the subject vehicle and the other vehicles-objects-subjects by the longitudinal relative speed of the subject vehicle and the other vehicles-objects-subjects.For pure crossing situations with constant speeds, unless differently specified in the text, this is obtained by dividing the longitudinal distance between the subject vehicle and the lateral line of movement of the other vehicles-objects-subjects by the longitudinal velocity of the subject vehicle.