In this paper, a three-dimensional geometrical noise model for single vehicles on a freeway is described. Its derivation is based on the propagation of sound energy from a point source in a free field. It is then generalized to all type of road vehicles by including in it between-type and within-type variations. The temporal characteristics of traffic noise is simulated using a digital computer from which statistical information is derived and traffic noise indices such as mean noise level, peak noise level, background noise level, noise pollution level, and equivalent steady noise level are evaluated. Close agreement was obtained between the predicted values and the measured values in five separate assessments of the model using freeways of three different speed limits in the state of New South Wales, Australia.