## 3 Dataset Description and Processing
### exiD Dataset  
The exiD dataset [13] is employed in this paper so as to comprehensively analyze merging behavior in the real world. The exiD dataset is available free of charge at [[https://www.exid-dataset.com](https://www.exid-dataset.com)]([https://www.exid-dataset.com](https://www.exid-dataset.com)) (20 September 2022). This dataset records real-world driving data of 69,172 vehicles at seven different locations of German freeway entrances and exits [13], and offers four files for each recording at every location. These four files include:  
1. Road cross-section image A georeferenced road cross-section image is added for each recording session. This image is created by applying filters to remove all moving vehicles from the recorded data.
2. CSV file describing the recording location This file contains the metadata for each recorded video, providing an overall summary of the recording session, such as the recording time, the segment of the road captured, and the total number of tracked objects.
3. CSV file containing an overview of recorded vehicle and Vulnerable Road User (VRU) trajectories This file contains an overview of all trajectories. The purpose of this file is to allow filtering of trajectories by category, such as based on the type of objects.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Author**} & \multirow{2}{*}{**Dataset**} & \multirow{2}{*}{\begin{tabular}{c} **Driving Risk** \\ **Analysis** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Consider the** \\ **Critical Moments** \\ **and Situation** \\ \end{tabular} } & \multicolumn{2}{c}{\
\begin{tabular}{c} **Consider** \\ **Heterogeneity** \\ \end{tabular} } & \multicolumn{1}{c}{
\begin{tabular}{c} **Application of** \\ **HD Map** \\ \end{tabular} } \\ \hline
2010 & [PERSON] et al. [14] & NGSIM & N & N & N & N \\  & & Two On-ramp & & & & \\
2014 & [PERSON] et al. [16] & Bottlenecks in & N & N & N & N \\  & & Shanghai, China & & & & \\
2019 & [PERSON] et al. [17] & NGSIM & N & N & N & N \\
2022 & [PERSON] et al. [6] & INTERACTION & Partial & N & N & N \\
2022 & [PERSON] et al. [18] & INTERACTION & Partial & Partial & N & N \\  & & Outer Ring & & & & \\
2022 & [PERSON] et al. [19] & Expressway, Shanghai, & Partial & N & Y & N \\  & & China & & & & \\
2023 & [PERSON] et al. [12] & AD4 CHE & Partial & Partial & N & N \\  & Our study & exiD & Y & Y & Y & Y \\ \hline \hline \end{tabular}
\end{table}
Table 1: Spatiotemporal merging behavior patterns assessment.  
* (4) CSV file containing trajectory data This file contains all time-related values for each trajectory, including information such as the current position, speed, and acceleration. The variables in this paper follow the settings in the exiD dataset, with detailed descriptions of the key variables provided in Table 2. For explanations of other variables, please refer to the official website.  
Through the single-frame images in Figure 1, we can gain a brief understanding of the conditions at seven locations. Seven collection locations are similar, but they differ in terms of road conditions, mainly the number of lanes and the presence of diversion sections. There are two consecutive merging at location 0. There is an intertwined area at Location 1. There is not a lane reduction working condition at Location 4, which leads to differences in vehicle driving behaviors. Therefore, this paper selects the vehicles collected in Locations 2, 3, 5, and 6. It will be studied in future articles for special consideration.