Nowadays, with the number of vehicles increasing rapidly, road traffic congestion in urban areas becomes a significant issue. In this paper, a dynamically restricted road segments protocol is proposed for quickly evacuating vehicles from the area and prohibiting vehicles from entering into the area where traffic congestion happens. The trajectory information maintained in the server assists determining the size of restricted area. The server determines the restricted area where the event occurs and then checks the position of all cars to adjust the size of restricted area. If vehicles are in the restricted area, the sever uses car-flow scheme to let the vehicles leave the restricted area. The other vehicles which are out of the restricted area obtain a path to avoid the area. The simulation results demonstrate that the work, on average, could reduce 10% travel time to evacuate vehicles, compared to the shortest path algorithm.