A deterministic method of assigning traffic to multiple routes of known cost

a method is proposed for assigning road traffic to a network of urban streets. the objective is to predict the flows along alternative routes with the accuracy needed for the design of comprehensive urban traffic management schemes. the method assumes that drivers vary in their perception of costs and choose the route that is best for them. the distribution of perceived costs is, for each link in a network, assumed to have a known average value and variance. a simple set of the deterministic relationships is derived which can be solved efficiently in a digital computer. the proportion of traffic using one of two routes is derived as a quadratic function of the difference in average costs and the relative variance in perceived costs. a network is solved by successive combinations of pairs of routes. a simulation program has been written to check the theoretical predictions. there is, as yet, no evidence that these predictions fit reality. it is suggested that some aspects of trip generation and choice of mode in addition to choice of route, may be analysed by the proposed method.(a)