Route Optimization Model for Hazardous Materials Transportation Considering Traffic Restrictions and Delivery Time Windows

Abstract

The government s strict traffic control and the requirement of enterprise logistics efficiency make the hazardous materials transportation process more complex. The challenge of existing hazardous materials transportation is to determine vehicle routes that minimize risks based on cost considerations of customer needs and road closures. According to the objective of minimizing risk and cost, a bi-objective integer programming model with joint constraints of road closure time window and delivery time window is constructed and solved by adaptive weight genetic algorithm. The case study of practical transportation network shows that the model can reasonably plan the node closure time of each route and the departure time of vehicles, and obtain a variety of optimal combinations of transportation schemes, so as to obtain the optimal strategies with different preferences for decision-making and provide decision support for the optimization of hazardous materials transportation route. Introduction Hazardous materials are flammable, explosive, poisonous, corrosive, contagious and radioactive, so once accidents occur in the transportation of hazardous materials, it will cause serious casualties, economic losses and huge environmental pollution and destruction to the society. According to the report of the State Administration of Work Safety of China, 1058 hazardous chemical accidents occurred between 2011 and 2015, resulting in 1375 deaths [1]. In order to effectively control the transportation risk of hazardous materials, the government has issued a series of relevant laws and regulations to prohibit hazardous materials vehicles from passing in a certain period or section of the road. And government departments usually impose temporary traffic restrictions on hazardous materials vehicles during festivals, important meetings or extreme weather. To reflect this practical constraint, a term called node closure time window is introduced. These closure time window restrictions may result in vehicles having to wait or park in certain locations. Considering the inherent characteristics of hazardous materials, the waiting time at some nodes in the transportation process may reduce the overall risk due to the time-varying risk attributes. On the other hand, for hazardous materials transportation enterprises, the restriction brings about the increase of transportation costs and the decrease of logistics efficiency. However, in addition to traffic restrictions, delivery time window should be considered as an important constraint factor in the transportation process of hazardous materials, which is closely related to customer experience and satisfaction. In the process of hazardous materials transportation, vehicles usually arrange their routes according to a specific delivery time window. In addition to risk minimization, customer satisfaction plays an important role in the effective route decision-making. Because of the importance and validity of reducing the risk of supply chain network, the research on the route optimization of time window related to hazardous materials is usually expressed as the optimization problem of cost, risk or the dual objective including both and risk fairness constraints. Zografos and Androutsopoulos [2] first linked the vehicle routing problem with time windows directly to the transportation of hazardous materials. Meng et al. [3] proposed a new vehicle routing and scheduling problem for hazardous materials transportation in multi-attribute time-varying