The Rollon–rolloff Vehicle Routing Problems in the Waste Management

Abstract

This dissertation introduces two waste collection vehicle routing problems. The rollon–rolloff vehicle routing problem (RRVRP) and the rollon–rolloff vehicle routing problem with time windows (RRVRPTW) assume that customers—such as in construction sites and in shopping districts—accumulate considerable amount of garbage in large waste containers. Tractors transport a container at a time between customers and waste facility locations such as a depot, disposal sites and container storage yards. The RRVRP considers a single disposal site and assumes that an unlimited number of containers with identical size and type are stored at the site. The RRVRPTW is a more general problem in which there are more complicated constraints arising from multiple disposal sites

multiple container storage yards

time windows for customer demands and facilities

various types and sizes of containers

and tractor driver’s lunch breaks. The problem further deals with real-world issues, such as changing service types, multiple demands at a customer’s location, and tractors with different work schedules. The objective of the problems is to determine routes that minimize the number of required tractors and their total route time to serve all given customer demands. This study introduces mathematical models and proposes a large neighborhood search (LNS) based iterative heuristic approaches for both problems. The effectiveness of the proposed heuristic methods is demonstrated by computational experiments by using benchmark data, some of which are derived from real-world problems.