Optimal Evacuation Model of Parking Vehicles in Dynamic Traffic Flows

In order to develop an effective evacuation plan for vehicles in a parking lot and achieve the shortest evacuation time, an optimal evacuation model was built by considering the dynamic traffic flow characteristics of a road network. Firstly, according to queuing theory, the vehicle queue on each exit lane of a parking lot was denoted by an M/M/1/1 queuing system, which was used to simulate how the traffic flow headway on the exit lane affects the vehicle departure rate, and estimate the queue time of the vehicles in the parking lot. Secondly, the traffic flow equilibrium model of road network nodes and link traffic flow equilibrium model were employed to imitate the path selection behavior in vehicle evacuation, and the evacuation time and delay time at intersections were estimated. Finally, a parking lot with 4 exits was selected to conduct an evacuation simulation. The results show that the traffic flow headway on the exit lane has a significant impact on vehicle queue time, travel time and evacuation time, while the optimal route choices are mainly affected by background traffic, demonstrating that the proposed model can simulate the dynamic traffic characteristics and time consumption during the evacuation process and adjust the departure rate to improve the evacuation efficiency according to the traffic flow headway.