# Vehicle Delay Model Applied to Dynamic and Static Traffic Impact Analysis of Large Parking Lots
## 3 Parameter Calibration of Vehicle Delay Model  
The direct determination of the parameters in the above delay model is a very complex task because it is affected by many factors, most of which are uncertain and inaccurate. At present, mainstream delay models such as the Webster model [22], the Miller model [7], the HCM 2000 model [23] mainly calibrate parameters indirectly through the data collected by traditional detectors. However, the data collected by the traditional detector has the disadvantages of poor reliability and low comprehensiveness, and it is not real-time, resulting in a large gap between the results and the actual situation. Moreover, it cannot handle many variables and interactions defined in the model in this paper. However, the simulation experiment has strong repeatability and can realize the simulation of large samples and multiple scenes. By setting the simulation environment, the simulation effect can be very close to the real situation. Therefore, this paper proposed to use the simulation experimental data calibration method to determine the parameters of the delay model, and finally got the vehicle delay value. Figure 3: Delay of Road Vehicles in Three Lanes on the Same Side. Due to the complete driving behavior model and fine facility description of the VISSIM platform, it can better restore the characteristics of facilities and make the simulation effect closer to reality. At the same time, several interfaces are provided for secondary development. Therefore, VISSIM was selected as the parameter calibration platform of the delay model in this paper. The vehicle delay is obtained by inputting traffic volume and other data, and the calibration of model parameters would be completed. The specific steps of the simulation experiment data calibration method are as follows. **Step 1:** Obtain the basic data required for simulation scene modeling. It mainly includes road data, entrance, and exit channel data, and driving path ratio data. (1) Road data. It includes the number of lanes connecting the road, lane width, lane design speed, and section length. (2) Parking ramp/ Entrance and exit channel data. It includes the geometric dimension data of the entrance and exit channel, the angle between the entrance and exit and the connecting road, the position of the gate in the entrance and exit channel, the average time for vehicles to pass through the gate, the average time for vehicles to leave through the gate, the speed for vehicles to pass through the entrance without road vehicle interference and the speed for vehicles to leave through the exit. (3) Travel proportion data. It includes the proportion of entering the parking lot from different lanes and the proportion of driving into different lanes from the parking lot during peak hours. **Step 2:** Build a simulation scene. Build the road network scene in the simulation software, and set the attributes of road section parameters, entrances and exits, deceleration zone, and so on. **Step 3:** Correct the parameters of the simulation software. The headway [24] is used to correct the parameters of the car following the model in VISSIM, making the simulation animation closer to the real traffic operation and increasing the authenticity and reliability of the simulation. The basic principle of parameter correction is to input different parameter combinations to minimize the difference between the headway distribution of simulation output and that of field investigation. Because PSO (Particle Swarm Optimization) has the advantages of memory, no crossover and mutation operation, and fast convergence speed, PSO was used for correction in this paper. **Step 4:** Set the detector. Set up travel time detectors for road vehicles, arrival vehicles, and departure vehicles in the parking lot. **Step 5:** Calculate the average delay of the simulation vehicle. Input the traffic volume combinations of various types of vehicles and run the simulation experiment and monitor the delay of each vehicle.