Optimizing Route for Hazardous Materials Logistics Based on Hybrid Ant Colony Algorithm

Optimizing Route for Hazardous Materials Logistics (ORHML) belongs to a class of problems referred to as NP-Hard, and a strict constraint of it makes it harder to solve. In order to dealing with ORHML, an improved hybrid ant colony algorithm (HACA) was devised. To achieve the purpose of balancing risk and cost for route based on the principle of ACA that used to solve TSP, the improved HACA was designed. Considering the capacity of road network and the maximum expected risk limits, a route optimization model to minimize the total cost is established based on network flow theory. Improvement on route construction rule and pheromone updating rule was adopted on the basis of the former algorithm. An example was analyzed to demonstrate the correctness of the application. It is proved that improved HACA is efficient and feasible in solving ORHML. 1. Introduction Hazardous materials, which have different physical and chemical properties, have high risk during transportation, as a series of problems may arise in this process. Route optimization is a complex combinatorial optimization problem, which is a typical NP-complete problem and difficult to come up with a direct answer. It is a practical problem in urgent need of solution in which we can find the optimal plan under the restrictions quickly, accurately, safely, and economically. Optimizing Route for Hazardous Materials Logistics (ORHML) can be described as follows. Given a set of hazardous materials and an underlying network consisting of a number of nodes and capacitated arcs, we wish to find an optimal routing plan to ship the hazardous materials through the network at lowest cost without violating the capacity limits. ORHML models also appear as subproblems in more complicated models, such as distribution system design and capacitated network design. ORHML has attracted the attention of many OR researchers. Kara et al. [1] presented several route planning models of road. Verma and Verter [2] gave a number of route planning models of rail. Iakovou [3] provided route planning models of water. Miller-Hooks [4] modeled ORHML as a path selection problem in a stochastic time-varying network. Dell’Olmo et al. [5] finding a number of spatially dissimilar paths between an origin and a destination can also be considered in this area. Jin and Batta [6] presented a risk model that took into account the dependency to the impedances of preceding road segments. Erkut and Verter [7] proposed a collection of edges in place of an origin-destination route for a hazmat shipment, where travel on this path can be viewed as