Optimizing operational costs and service quality in dial-a-ride systems

Abstract

Dial-a-ride services typically provide collective on-demand transportation to people with reduced mobility, such as elderly and disabled. The demand for these services will increase in the coming years, due to demographic evolutions and developments in the healthcare sector. In addition, modern policy visions aim at integrating them into the regular public transportation network. Providers of dial-a-ride services need efficient vehicle routing algorithms, taking into account all real-life problem characteristics, to support their operational activities. In addition, solving this routing problem entails a considerable tradeoff of operational costs and service quality. From the perspective of a provider, the most efficient routing solutions are created by combining different users into the same ride. However, these users face inconvenience due to the resulting detours and potential deviations from their preference time. Rather than unilaterally minimizing the operational costs subject to a set of minimum quality requirements, this PhD thesis develops a bi-objective routing algorithm that provides insight into the tradeoff of operational costs and service quality. This allows providers to implement a strategic quality vision and to make operational decisions in line with this policy. The impact of various real-life operating characteristics is analyzed.