Scheduling Optimization of Vehicle Routing Problem with Time Windows for Hazardous Materials Transportation

Optimizing routes is important to reduce risk and cost of hazardous material transportation. Aiming at the vehicle routing problem with time window for hazardous material transportation, according to its characteristics, it is divided into bi-objective shortest path problem and bi-objective vehicle routing problem with time window. The mathematical models are established, and a two-stage method is designed to solve the problem. In the first stage, the pulse algorithm is used to filter the path to obtain the Pareto-optimal path between the distribution center and each demand node. In the second stage, considering the time window constraints and risk changes in the distribution, a spatial search method for the solution is proposed, the formulas of pheromone update and state transition probability are defined, and an ant colony algorithm is designed for the bi-objective vehicle routing problem with time window. Finally, the model and algorithm are verified by a case.