Empirical study on the effects of freeway emergency lane opening on vehicle-driving behavior

To clarify trajectory characteristics during lane-keeping on freeways with open emergency lanes, drones captured aerial videos of straight sections of the Lanhai Expressway. A hybrid YOLOX-Deep-SORT framework was used to extract vehicle trajectory data, and key oscillation metrics (lateral deviation, left lateral clearance, oscillation amplitude) were quantified under naturalistic driving conditions. Comparative lane analyses showed emergency lane opening increased inter-lane interactions: lateral deviations rose across all lanes (outer > emergency > inner), adjacent lanes’ oscillation amplitude increased by ~0.55 m (emergency lane vehicles had lower oscillations). Regular lanes shifted left (left clearance reduced by 0.5 m); 70% of emergency lane vehicles operated 0.50–0.79 m from right guardrails, with frequent boundary violations (minimum clearance: −0.18 m). Open emergency lanes may enhance adjacent lanes’ lateral instability and collision risks, providing a theoretical basis for safety-efficiency balanced emergency lane management.