INSTANTANEOUS TRAFFIC ASSIGNMENT UNDER DEMAND UNCERTAINTIES

Traffic queues, as they cause extra queuing delays, will affect the route choices of travelers. However, the effects of instantaneous queues, which frequently occur, have received little attention. Instantaneous queues, caused by short-term stochastic time-dependent traffic conditions, are formed and dissipated during instantaneous time intervals within an hourly period. This paper proposes a queue-dependent stochastic user equilibrium model with the consideration of instantaneous queuing effects in congested road networks under demand uncertainties. In the proposed model, instantaneous queues are determined according to the speed-flow fundamental diagram, and the corresponding queuing delay is determined and included in the link performance function. The proposed model is formulated as a variational inequality problem to estimate link flows and speeds at different instantaneous time intervals under stochastic traffic conditions. A numerical example is used to demonstrate the characteristics of the proposed model. Lastly, recommendations for further studies are provided.