A Bi-Level Approach to Vehicle Fleet Reduction: Successful Case Study in Community Healthcare

Citation

Brownlee AEI, Thomson SL & Oladapo R (2024) A Bi-Level Approach to Vehicle Fleet Reduction: Successful Case Study in Community Healthcare. In: Genetic and Evolutionary Computation Conference 2024, Melbourne, Australia, 14.07.2024-18.07.2024. GECCO '24: ACM. https://doi.org/10.1145/3638530.3664137

Abstract
We report on a case study application of metaheuristics with Argyll and Bute Health and Social Care Partnership in the West of Scotland. The Partnership maintains a fleet of pool vehicles that are available to service visits of staff to locations across a largely rural area. Maintaining such a fleet is important but costly: we show how the allocation of fleet vehicles can be formulated as a bilevel optimisation problem. At the upper level, vehicles are allocated to 'base' locations such as hospitals. At the lower level, vehicles are allocated to specific jobs. We explore local-search approaches to solving this problem. We show that some blurring of the distinction between upper and lower levels can be helpful for this problem. We also demonstrate, for our case study, a 7.1% reduction in the vehicle fleet while still being able to meet all demand.

Keywords
Optimal job scheduling; evolutionary computation; bilevel optimization