Modified Ant Colony Algorithm for the Vehicle Routing Problem with Time Windows

Vehicle Routing Problem with Time Windows (VRPTW) is an NP-Complete Optimization Problem. Even finding an optimal solution for small size problems is too hard and time-consuming. The objective of VRPTW is to use a fleet of vehicles with specific capacity to serve a number of customers with dissimilar demands and time window constraints at minimum cost, without violating the capacity and time window constraints. This problem has been solved with a number of heuristic and meta-heuristic solution algorithms and optimal or near optimal solutions gained. In this paper, a modified Ant Colony algorithm is proposed. In this algorithm we tried to simplify the solution procedure and computational complexities of ant colony meta-heuristic. To gain this capability, we sacrificed some computational accuracy. Testing the solution procedure on the Solomon test-problems showed that this algorithm is capable of generating relatively good solutions.