# Driving Behavior Modeling Based on Consistent Variable Selection in a PWARX Model
## 5 Model Evaluation
### Car-Following Simulation  
The applicability of the proposed model is investigated by closed-loop behavior verification. To this end, a car-following simulation was designed and implemented using both the identified (proposed) driver model and the Gipps driver model. To make the simulation as close to real-world autonomous driving as possible, the CARLA driving simulator in combination with a ROS (Robot Operating System) was adopted. Using the CARLA driving simulator, sensors such as 3D Lidar, Camera, GNSS can be mounted on the vehicles, and the data received from these sensors can be processed (mapping, localization, detection, etc.) using ROS. In addition, the vehicles used in the CARLA simulator have dynamics modeled from actual real-road vehicles. Thus, the framework used here for the simulation is as close as possible to that used in a real-world autonomous car-following task. The setup for the car-following simulation is shown in Figure 10.  
This verification involves embedding together the identified driver model with the vehicle model and calculating the closed-loop behavior. The procedure for the verification is as follows:  
**Step 1:**: Initialize the states of the ego car and leading car, in this case, position and velocity.
**Step 2:**: Based on the states, the input data of the driver model (\(u_{1}{\sim}u_{6}\)) are computed.
**Step 3:**: The mode is decided based on SVM and the corresponding input data of the driver model are updated.
**Step 4:**: Using the identified driver model, the output (speed of ego car) is computed.
**Step 5:**: Update the states of the ego and leading cars based on the output of Step 3 and the leading car's velocity pattern.
**Step 6:**: Go to Step 2.  
A similar procedure is adapted for the Gipps driver model by using the Gipps driver model to compute the output in Step 4, and removing Step 3.  
The profiles from the simulation by using the identified driver model and the Gipps driver model together with the corresponding profiles from the real-road driving experiment data are shown Figure 11. It could be verified that the identified driver model was able to follow the leading car without collision, nor lagging far behind the leading car. However, even though the Gipps model could follow the leading car without any collision, although at some point it started lagging far behind the leading car. Furthermore, comparing the profiles to that of the actual real-road driving (Figure 11), the profiles of the identified model mimic better than that of the Gipps model. Therefore, it is confirmed that the original behavior is well reproduced by the identified model. A short video of the simulation is shown, respectively, [[https://youtu.be/jfyM5](https://youtu.be/jfyM5) msDu2k]([https://youtu.be/jfyM5](https://youtu.be/jfyM5) msDu2k) (accessed on 18 May  
Figure 10: Setup used for the car-following simulation: A bridge between CARLA driving simulator and ROS.  
2021) for [PERSON] driver model and [[https://youtu.be/8Q0n3](https://youtu.be/8Q0n3) iaNbxE]([https://youtu.be/8Q0n3](https://youtu.be/8Q0n3) iaNbxE) (accessed on 18 May 2021) for the proposed model.