Urban Expressway Pricing under Constraint

Four radials-single ring urban expressway network is priced and, simultaneously, optimized in its spatial formation under the constraint that a balance must be kept of revenue and expenditure. The model consists of three sub-models: road system, car trip generation-attraction and traffic diversion. Network performance is assessed on two criteria; trip number criterion on which the aggregate number of car trips diverted onto expressway is maximized and travel hour criterion on which the travel hours of car trips integrated over the road system; surface and expressway, is minimized. Optimization is tried by numerical calculation for some sets of parameters in the model. The results are summarized as follows; (1) simultaneous optimization of price and spatial formation of the expressway network is possible on each of criteria, (2) trip number criterion produces lower pricing and smaller network while travel hour criterion does higher pricing and larger network, (3) optimum solution lies in a delicate relation of price and spatial network formation that comes from the balance constraint.