Advanced Quantum Annealing Approach to Vehicle Routing Problems with Time Windows
James B. Holliday, Darren Blount, Eneko Osaba, Khoa Luu
TL;DR
This paper investigates applying quantum annealing to complex routing with time windows by integrating D-Wave's Constrained Quadratic Model (CQM) into a hybrid HQTS framework. It shifts from QUBO to CQM to explicitly model time-window constraints, introduces arrival-time and sequencing variables to improve feasibility, and deploys a post-processing swapping heuristic to repair infeasible solutions. Across Solomon benchmark instances, the approach achieves an average optimality gap around $3.86\%$ and demonstrates competitive performance relative to Google OR-Tools, highlighting the potential and limitations of quantum-classical integration for real-world vehicle routing with time windows. The work emphasizes the importance of feasibility-focused post-processing in practical quantum optimization and sets a foundation for broader, scalable quantum-assisted routing research.
Abstract
In this paper, we explore the potential for quantum annealing to solve realistic routing problems. We focus on two NP-Hard problems, including the Traveling Salesman Problem with Time Windows and the Capacitated Vehicle Routing Problem with Time Windows. We utilize D-Wave's Quantum Annealer and Constrained Quadratic Model (CQM) solver within a hybrid framework to solve these problems. We demonstrate that while the CQM solver effectively minimizes route costs, it struggles to maintain time window feasibility as the problem size increases. To address this limitation, we implement a heuristic method that fixes infeasible solutions through a series of swapping operations. Testing on benchmark instances shows our method achieves promising results with an average optimality gap of 3.86%.
