## 4 Results
### Conflict Analysis through PCRI Using the ORED
In this case, it can be assumed that both vehicles are essentially on the same lane, making rear-end conflicts more probable. There are a total of 278 instances in this category, accounting for 43.1% of the total. For the two most likely conflict types involving cars and trucks, further analysis is conducted on the distribution of locations where these conflicts occur. Figure 19 shows the spatial distribution of the locations of lane-changing (type 1) and rear-end (type 2) conflicts. Based on Figure 19a, the horizontal position of conflicts on the video frame gradually shifts downstream with lane sequence, progressing from 150 m to 110 m, then to 70 m, and finally to 30 m. This demonstrates the lag in lane-changing conflicts. In Figure 19b, rear-end conflicts mainly occur on the sections of the on-ramp that are about to merge into \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Lane 1** & **Lane 2** & **Lane 3** & **Lane 4** & **Lane 5** & **All** \\ \hline Average & 29\% & 68\% & 69\% & 35\% & 2.0\% & 34\% \\ Min & 18\% & 38\% & 46\% & 11\% & 0.0\% & 26\% \\ Max & 58\% & 86\% & 95\% & 72\% & 10\% & 47\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Statistics of truck proportions by lane. Figure 16: The proportion of trucks and cars. Considering the vehicle types, there are three different conflict patterns: car-car, car-truck, and truck-truck. The statistical indicators of conflict are summarized by different conflict patterns as shown in Table 5. Apart from the horizontal position on the video frame, the differences between the average indicators for different conflict patterns are minimal. The average PCRI for truck-truck conflicts tends to be slightly higher. The distribution of conflict locations under different conflict patterns is shown in Figure 20. As depicted in Figure 20, car-car conflicts are mostly distributed on the left side of the study area, which is related to the frequent lane-changing behavior of small cars downstream of the merging area. Car-truck conflicts are mostly distributed on the left side as well, but compared to the former, this kind of conflict is concentrated to some extent in the area where the entrance ramp traffic merges with the mainline traffic (approximately at the 150 m mark). As for truck-truck conflicts, their locations are mostly distributed in the merging area and on lane 3, indicating that conflicts between trucks are more likely to occur in the downstream section of the mainline merging area, attributed to the lane-changing behavior of trucks at the entrance and the higher proportion of trucks on lane 3. In Figure 21a, when car-truck conflicts occur, the horizontal distance difference on the video frame between two vehicles is smaller than that of truck-truck conflicts due to the difference in vehicle sizes and braking performance between trucks and cars. Meanwhile, according to Figure 21b, the vertical distance difference on the video frame in car-truck conflicts is higher than that in truck-truck conflicts. This is because the proportion of lane-changing conflicts between cars and trucks is 61.7% which is higher than lane-changing conflicts between two trucks with a proportion of 45.0%. Figure 21: The position difference in different conflict patterns. Figure 20: The positions of different conflict patterns.