Impact of trucks on traffic flow in expressway diverging areas

To explore the impact of trucks in freeway diverging areas, this paper presents an enhanced cellular automaton model. The model refines vehicle acceleration, deceleration, and position update rules while integrating truck-specific factors to better analyze their effects on traffic safety and efficiency in diverging areas. At the macro level, this paper primarily considers three factors: main road traffic volume, diverging ratio, and truck proportion. At the micro level, it focuses on two factors: truck length and the number of vehicles in a truck platoon. Results show that, at the macro level, when the main road truck proportion exceeds 40%, and the diverging ratio surpasses 15%, and at the micro level, when truck length exceeds 20 m, and the number of vehicles in a truck platoon exceeds three, trucks significantly impact traffic operations of diverging areas, indicating the formation of truck barriers. Subsequently, this paper further examines the safety implications of truck barriers in freeway-diverging areas. The results demonstrate that the formation of truck barriers leads to a significant increase in traffic conflicts within diverging areas, posing substantial safety risks to normal traffic operations.