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arXiv · 2601.11467

The XL Instances and the CVRPLib Best Known Solution Challenge

Eduardo Queiroga·Rafael Martinelli·Anand Subramanian·Eduardo Uchoa·Thibaut Vidal
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Abstract

This paper introduces the XL set, a new collection of large-scale benchmark instances for the capacitated vehicle routing problem (CVRP). The set extends previous benchmarks by covering instances with 1,000 to 10,000 customers and a wide range of structural characteristics, following established generation principles from prior CVRP studies. To provide strong reference solutions, we conducted an extensive computational study with several state-of-the-art algorithms and retained the best solutions obtained as the starting point for a community-driven BKS challenge hosted on the CVRPLib website. The XL instances are publicly available to support the experimental evaluation and comparison of future solution methods. The post-competition results demonstrate the impact of the challenge: over 30 days, participating teams submitted 1,932 BKS improvements, substantially refining the initial solution set and highlighting promising research directions for solving large-scale CVRPs, notably through LLM-assisted algorithm discovery.

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Eduardo Queiroga, Rafael Martinelli, Anand Subramanian, Eduardo Uchoa, Thibaut Vidal. 2026-01-16. The XL Instances and the CVRPLib Best Known Solution Challenge. https://arxiv.org/abs/2601.11467

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