The Dial-a-Ride Problem in Primary Care with Flexible Scheduling

TL;DR

This paper introduces a novel extension of the dial-a-ride problem that incorporates flexible scheduling for primary care patient transportation, improving request utilization and ride sharing efficiency.

Contribution

It proposes two heuristics exploiting scheduling flexibility in the DARPCF, enhancing request bundling and transportation efficiency.

Findings

Average served requests increased by 16% with flexible scheduling.

Heuristics effectively exploit scheduling flexibility for better routing.

Flexible scheduling leads to higher system utilization.

Abstract

Patient transportation systems are instrumental in lowering access barriers in primary care by taking patients to their GPs. As part of this setting, each transportation request of a chronic or walk-in patient consists of an outbound trip to the GP and an inbound trip back home. The economic sustainability of patient transportation systems mainly depends on their utilization and how well transportation requests can be bundled through ride sharing. To ease the latter, we consider a flexible scheduling of chronic patients in which only a certain range for an appointment is fixed a priori while the exact time is determined by the scheduling of the outbound trip. This leads to a novel extension of the dial-a-ride problem that we call the dial-a-ride problem with combined requests and flexible scheduling (DARPCF). In this paper, we introduce two heuristics for the DARPCF that exploit this increased flexibility. Both approaches initially compute so-called mini-clusters of outbound requests. Then, the mini-clusters are linked by (i) solving a traveling salesman problem and creating routes of outbound rides with a splitting procedure or by (ii) using a rolling horizon approach and solving bipartite matching problems for the vehicle assignment. Our computational study shows that by using the presented algorithms with the flexible scheduling of chronic appointments, the average number of served requests can be increased by 16% compared to a non-flexible setting.