Modeling road network capacity and service level under variable demand pattern

The relationships among the capacity, service level and travel demand pattern of urban road networks are mainly investigated. The zonal reserve capacity is defined and adopted as an integrated performance index to road network capacity. Mathematically, it is formulated as a bi-level model. On the one hand, the requirements for travel time on Origin-Destination(O-D) pairs are converted into explicit capacity constraints of dummy links by modifying the network representations. On the other hand, the presumption of fixed travel demand pattern among all O-D pairs is eliminated. The trip distributions are determined by the Logit model according to the O-D travel time and trip attraction abilities of destination zones. Finally, a numerical example is provided to demonstrate the validity of the model and algorithm.