Evaluating the Impact of CAV-Dedicated Lanes on Freeway Capacity and Safety: Findings from Simulation Experiments
This study built a modified simulation environment in SUMO to evaluate dedicated lane (DL) policies for connected and automated vehicles (CAVs) on a 102 km bidirectional eight-lane freeway modeled after the Beijing-Xiong'an Freeway. Using LandScan population density data to generate traffic demand, the researchers simulated five experimental scenarios to measure traffic efficiency, capacity, and safety under different CAV penetration rates and lane placements. The results show that a single dedicated lane is sufficient when CAV penetration is under 20%, and that placing the DL on the outermost lane is optimal when direct routes make up less than 60% of total demand, whereas placing it on the innermost lane during emergencies causes congestion that reduces average speeds by 30.77%.
Why it matters — It provides specific, spatial-configuration rules for freeway planners, demonstrating that the optimal placement of automated vehicle lanes depends directly on origin-destination distributions and emergency vulnerability rather than just penetration rates.
Caveat: The findings are derived entirely from simulation experiments modeled on a single, specific 102 km freeway corridor, which may not fully capture the driving behaviors and geometry of other highway networks.