Application of Simultaneous and Sequential Transportation Network Equilibrium Models to Riyadh, Saudi Arabia

The approach used in practice to predict short-run transport equilibria involves a sequential process, often with four stages: trip generation, trip distribution, modal split, and traffic assignment. This approach has an inherent weakness—its prediction need not be internally consistent. This deficiency has motivated attempts to predict all four stages simultaneously. The (conventional) sequential and simultaneous models are compared by calibrating and applying both models to the urban transportation network of Riyadh, Saudi Arabia. The main finding is that the simultaneous model produces better traffic flow predictions than the prediction of the conventional sequential model. These predictions are much better for the heavy volume links that are the most important links in the prediction process.