CAR-FOLLOWING MODEL RELATING REACTION TIMES AND TEMPORAL HEADWAYS TO ACCIDENT FREQUENCY.

Assessment of the sensitivity of collision probability to a shift in expected reaction time reduces to determining the sensitivity of the probability of ruin to changes in the drift of the process of cumulative differences between reaction times and temporal headways. A diffusion-type approximation is used and it is shown that additive changes in mean reaction time correspond to multiplicative changes in collision probability. A numerical example is given to illustrate the potential effects of a mere 0. 1 sec decrease in mean reaction time.