Traffic congestion at a two-tandem bottleneck

Equilibrium queuing patterns are analyzed in the context of a two-tandem bottleneck with two origins and one destination. The individual in the model chooses his/her departure time, considering the trade-off between travel time and schedule delay. At equilibrium, no one can alter his/her departure time in the sense of the Wardrop principle. Four different configurations are analyzed associated with the capacities of the upstream and the downstream bottlenecks and queuing start times at both bottlenecks. Queuing patterns are determined in the model. It is found that, in some cases, a queue does not occur at the upstream since the departure rate is always equal to its capacity level at equilibrium. Therefore, in order to avoid traffic congestion at a two-tandem bottleneck, the downstream should be enlarged prior to the upstream.