Safety performance analysis of toll plaza diverging area based on an improved simulation platform for weak-constraint driving behaviors

Toll plaza diverging area is a typical non-lane-based high-risk area characterized by frequent weaving and complex vehicle interactions. While observation-based approaches are effective for analyzing current safety conditions, they lack the flexibility in evaluating the safety impacts of infrastructure designs and traffic control strategies under future scenarios. To address this limitation, this study proposes a microsimulation-based approach to analyze the safety performance of toll plaza diverging areas by simulating the realistic conflict distributions under various traffic conditions. Based on the perception-decision-action (PDA) framework, the proposed approach improves the conflict simulation accuracy by more accurately modeling the weak-constraint driving behavior, including non-lane-based perception, dynamic toll lane selection, and car-following under weak-constraint conditions. Validated on real-world trajectory data from two distinct toll plaza diverging areas, the simulated conflict distributions by the PDA approach closely align with the observed data, while SUMO significantly underestimates the safety risks in diverging areas. Furthermore, a simulation platform is developed based on the PDA approach to quantitatively analyze the safety performance of toll plaza diverging areas under different diverging lengths and traffic volumes. Results indicate that insufficient diverging lengths increase severe conflicts, whereas excessively long diverging areas lead to inefficiencies without substantial safety benefits. This study provides novel insights into safety performance analysis in non-lane-based areas, offering a reliable simulation tool for optimizing management strategies in complex weaving scenarios.