Operational Effects of Service Level Variations for the Dial-a-Ride Problem

Abstract

The dial-a-ride problem consists of designing a number of minimum-cost vehicle routes in a system of demand-dependent, collective people transportation. Quality is ensured by taking into account service level requirements. However, little research has been conducted into the effect of service level variations on operational costs incurred by service providers. This study investigates the evolution of operational costs for 78 combinations of two service level parameters, being the maximum deviation from a user's preference time and the relative maximum exceedance of a user's direct ride time. A distinction is made between various operating circumstances, including the size of the service provider, the traffic conditions in the service area and the heterogeneity of the customers. The resulting tradeoffs between quality and costs should encourage service providers to make informed decisions regarding potential changes in the service level they offer. The sensitivity analysis in this paper is performed on well-known benchmark data from literature and applies a state-of-the-art deterministic annealing metaheuristic to compute operational costs.