Effects of Capacity Constraints on Peak Period Traffic Congestion

A model of peak period traffic congestion analyzes the effects of capacity constraints. The model predicts the temporal distribution of traffic volumes when the demand is elastic. In response to changes in traffic conditions travellers can switch to a different mode, alternate route. The delays are assumed to occur at bottlenecks and a queueing model is employed to determine the waiting time as a function of the length of the queue at the time of arrival at the bottleneck. The day to day adjustment of traffic is derived from a dynamic Markovian model. Numerical simulations demonstrate that elastic demand congestion may persist even when a bottleneck capacity is expanded to meet the highest level of existing traffic flows.