Estimation model and algorithm of multi-mode path flow

In order to calculate multi-mode traffic demand from traffic counts under congested conditions, a multi-mode path flow estimation model with stochastic user equilibrium was presented, and an augmented Lagrange dual algorithm was given. Link capacity, flow equilibrium and priori demand constraints were transformed into penalty functions. The original constraint optimal flow estimation model was transformed into non-constraint optimal model, and a simple projection algorithm was adopted for non-constraint optimal model. Simulation result shows that the smaller the priori demand error is, the better OD estimation results are; the priori demand error has little influence on link flow estimation result, therefore, the estination model and algorithm are simple and applicable.