Dynamic model for traffic concentration and congestion near bridge

We study the traffic flow and congestion near a bridge when many cars flow into the roads connecting a bridge at morning peak. We present a mathematical dynamic model for simulating the traffic concentration and congestion near the bridge. The dynamic model is described by differential equations on the decorated one-dimensional lattice with multiple inflows and outflows. The macroscopic dynamic equations of vehicular densities are derived. The time evolution of densities and currents is shown by solving the density equations numerically. It is clarified how and where traffic congestion generates due to a flood of cars near the bridge.