# Driving Behavior Modeling Based on Consistent Variable Selection in a PWARX Model
## 3 Analysis and Modeling of Driving Behavior
### Acquisition of Driving Data  
The strong point of the work presented here is the use of data acquired from a real road driving experiment. Most of the works geared towards driving behavior analysis use driving data from a driving simulator because of the relative ease at which experimental data can be collected. However, there is a gap between the driving data from the driving simulator and that from real road driving. This work aims to bridge this gap by developing a model suitable for real road behavioral data; therefore, a real-world driving experiment was designed.  
Figure 2: An example of selecting the optimal number of modes or sub-models using consistent variable selection, given 2 sets of clusters.  
This paper focuses on the driver's car-following task in the downtown road and, accordingly, the location was chosen to be Sakae (GPS coordinates: 35.1698544, 136.9081513) the downtown area or city center of Nagoya city, Japan. This is a typical downtown area with high traffic volume, and with relatively flat topography. The driving route is shown in Figure 3.  
For collecting the driving data, a sensor setup consisting of a 3D LiDAR, a USB camera, and an OBD CAN reader mounted on a Toyota Prius 2015 model was used. Through the OBD CAN reading, driving information such as vehicle speed, throttle pedal position, brake pedal position, and wheel speed was measured. The USB camera was fused with the 3D LiDAR to detect and measure the position of the surrounding traffic entities like the leading vehicle. Figure 4 shows the sensors that were mounted on the car used in this driving experiment.  
A total of 6 drivers (A, B, C, D, E, and F), each with more than three years of driving experience, took part in this driving experiment. As shown in Figure 3, two courses (A and B) each with a length of 1.3 km were chosen for the driving experiment, with driving conducted at varying times of the day to reflect the change in traffic volume of the selected driving courses. Deliberate consideration was made to ensure that the driving experiment included peak traffic hours. Each driver drove five times on each course totaling about an hour of driving and was instructed to drive normally as they would drive in an everyday situation. Furthermore, since the point of interest was observing car-following driving behavior, the drivers were instructed to keep the middle lane and were not allowed to change lanes throughout the driving experiment. Only the ego (following) vehicle was controlled during the experiment, therefore ensuring a naturalistic interaction between the surrounding entities. This experiment was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethical Committee of Graduate School of Engineering, Nagoya University with approval number of 18-6. The video of a sample  
Figure 4: Sensor setup for collecting the real-road driving data.  
Figure 3: Route of the driving experiment (Sakae) showing the two courses (Course A and Course B), with the relative GPS coordinates of the area.  
run of the driving experiment which shows the actual traffic and environmental conditions is shown [[https://youtu.be/LBM3](https://youtu.be/LBM3) PTIfecQ]([https://youtu.be/LBM3](https://youtu.be/LBM3) PTIfecQ) (accessed on 18 May 2021) for course A and [[https://youtu.be/AeOn3](https://youtu.be/AeOn3) bxFzQQ]([https://youtu.be/AeOn3](https://youtu.be/AeOn3) bxFzQQ) (accessed on 18 May 2021) for course B.