How can a Dutch poffert arrive 450 miles away the next day? Middle-mile logistics optimization. This segment covers the longest distance, drives costs, and determines freshness. Research has focused on first and last mile, modeled as vehicle routing problems (VRP). The middle mile, moving goods between distribution centers regionally or continentally, has received less attention despite its cost. Progress is hindered by a lack of public data; companies treat network topologies and demand as proprietary.

Middle-mile logistics spans factory-to-consumer, parts to car manufacturers, and temperature-controlled pharmaceuticals. To address missing standardized data, in “A Novel Instance Generator for Simulating Middle-Mile Logistics Networks”, we introduce Mille Miglia, a C++ instance generator for realistic benchmarks. Source code and documentation are on GitHub.

The logistics spectrum: first, middle, and last mile differ by shipment journey. First and last mile keep a shipment in one vehicle from origin to destination, optimizing assignment and sequencing over a day. Middle mile acts as a relay race: a shipment may use several vehicles across a continental network, arriving a week later. For example, goods from Groningen move to Utrecht, then Paris, before delivery in Versailles.