Problem size reduction methods for large CVRPs

We solve the Capacitated Vehicle Routing Problem (CVRP) by introducing a novel approach to problem size reduction. We propose the generation of short sequences of nodes called “sections”, which effectively act as single nodes in a reduced CVRP that is faster and easier to solve. Three section generation methods are compared, and the trade-off between solution quality and computation time savings is evaluated. We show that reduced problem sizes of up to around 60 percent of the original problem size, result in only modest decreases in solution quality, but allow for significant reductions of computation time, regardless of the optimization algorithm used. Our findings highlight the potential benefits of problem aggregation and size reduction for large-scale CVRPs and suggest opportunities for further improving aggregation methods.