Vehicle Routing Problem with Stochastic Travel Times: Balancing Service and Transportation Costs

This paper studies a vehicle routing problem with soft time windows and stochastic travel times. A model is developed that considers both the transportation costs (total distance traveled, number of vehicles used and drivers' total expected overtime) and the service costs (early and late arrivals). We propose a Tabu Search method to solve our model. Different initial solutions are used to examine the trade-off between computation time and solution quality. An initialization algorithm is developed to construct feasible routes by taking into account the travel timestochasticity. Solutions provided by the Tabu Search algorithm are further improved by a post-optimizer method. We conduct our computational experiments for well-known problem instances. Results show that our Tabu Search method performs well by obtaining very good final solutions in a reasonable amount of time.

Tom Van Woensel is Associate Professor of Operations Management and Logistics at the Technische Universiteit Eindhoven in the Netherlands.
He holds an MSc in Applied Economics and a PhD in Operations Management from the University of Antwerp (Belgium). After the completion of his PhD, he moved to the Eindhoven University of Technology where he started as Assistant Professor (2003-2010) with a specialization in Retail Operations, distribution logistics and the analysis of manufacturing systems.
Today, his research is mainly focused on transportation planning under uncertainty and retail operations. He published over 30 papers in academic journals (including Management Science, Production and Operations Management, Computers and Operations Research, Transportation Research, European Journal of Operational Research, Journal of Mathematical Modeling and Analysis, and International Journal of Production Economics) and several chapters in international books.
Van Woensel is also a board member of the European Supply Chain Forum, a collaborative effort with about 20 large multinational companies.
He also holds a visiting appointment at the Université Catholique Louvain (Belgium). In the past, he had visiting appointments at the University of Antwerp (Belgium), Lessius University College (Belgium) and the MIT-Zaragoza Logistics Center (Spain)