Abstract
An analytical model using the lognormal probability density function is applied to published driver response time measurements. Close agreement is obtained when this function is fitted to the measuredresponses of drivers to the onset of the amber signal as they approach signalized intersections. Statistical parameters associated withthree sets of measured data are presented. Parametric estimates of 1.1 To 1.2 Sec for the median, 1.3 To 1.4 Sec for the mean, and 0.55To 0.75 Sec for the standard deviation of the distribution functionappear to give the best fit to the experimental values. This paper appears in transportation research record no. 1213, Human performance and highway visibility: design, safety, and methods.