An ant colony optimization algorithm for waste collection vehicle routing with time windows, driver rest period and multiple disposal facilities

In this paper we consider a real life waste collection problem that can be seen as a variant of the vehicle routing problem with time windows. In this problem there is a set of clients to be served, a number of facilities where the collected waste must be disposed off and an infinite number of vehicles stationed in a single depot. Each client has a definite time window within which it must be served. Each disposal facility must also be used within a given time window. Similarly, there is a time window associated with the depot, within which the vehicles must return to it. Additionally, there is a fixed lunch period for the vehicle drivers. Our goal is to solve the problem using minimum number of vehicles and minimizing the total distance crossed by the vehicles. In this paper, we solve the problem using an Ant Colony Optimization (ACO) algorithm. Experimental results indicate that our algorithm provides better results than the previous algorithms.