An Optimization Method of Catch-up Speed for Highway Truck into Formation Considering Generalized Cost

The formation by trucks equipped with connected and autonomous driving technology reduces the fuel consumption of vehicles and increases transport efficiency. This study focuses on highway freight trucks, and the functions of fuel cost and time cost were established based on vehicle dynamics theory and transportation economics. A platoon benefit function was developed combined with the functions of fuel cost time cost. Subsequently, an optimization model for the catch-up speed during the platooning process was established. To analyze the effects of the speed of vehicles and formations on the optimal catch-up speed, a transportation from Changchun to Shenyang in China was used as a case study, and the impacts of air resistance variation coefficient and distance between vehicle and formation on platoon benefits were discussed. The results indicate that the platoon benefit decreases by 16.49% when the distance between vehicle and formation increases from 0.2 km to 5 km, and the benefit decreases by 64.87% when the in-platoon air resistance variation coefficient increases from 0.6 to 0.95, which demonstrates that joining a closer platoon will yield greater benefits when multiple formations are available. Furthermore, a lower in-platoon air resistance variation coefficient increases the likelihood of joining that platoon.