Multi-depot multi-trip vehicle routing problem with time windows and release dates

Abstract

This study investigates a multi-depot multi-trip vehicle routing problem with time windows and release dates, which is a practical problem in the last mile distribution operations. This problem aims to design a set of trips for the fleet of vehicles supplied by different depots for minimizing total traveling time. It addresses some realistic considerations, such as the customers’ time windows and the release date of customers’ packages. The problem is formulated as a mixed integer programming model. A hybrid particle swarm optimization algorithm and a hybrid genetic algorithm are developed to solve this problem. Extensive numerical experiments are conducted to validate the effectiveness of the proposed model and the efficiency of the proposed solution methods. The experimental results show that our proposed algorithms can obtain near-optimal solutions for small-scale problem instances, and solve some large-scale instances with up to 200 customers, 20 depots and 40 vehicles in reasonable computation time.