How Traffic Density and Trucks Influence Discretionary Lane Changes on Freeways: An Empirical Analysis

This study examines discretionary lane-changing behavior under different traffic conditions, based on real-world freeway vehicle trajectories from the highD and Zen datasets. Statistical analysis is performed to explore the impacts of various operational characteristics of the freeway, including traffic density and truck proportion, on the frequency of lane changes. The results reveal the relationship between the overall density and the number of lane changes, which remains relatively consistent across different road configurations (four or six dual freeways). Additionally, the presence of trucks significantly influences drivers' lane-changing behavior, with the highest frequency of lane changes observed when there is a moderate difference in truck proportion between lanes. This finding challenges the hypothesis that a greater disparity in truck proportion leads to more lane changes. Under conditions with different traffic density and truck presence, we associate drivers' discretionary lane-changing behavior with traffic conditions, regulations, psychology, and slow-moving truck effects. The insights of this study can provide valuable guidance for traffic operators and autonomous vehicles in road resource allocation and intelligent lane choices, thus improving overall freeway safety and efficiency.