Abstract

Optimizing vehicle routing is an essential problem of the global economy that has engaged computer scientists since the 1950s. Today, the technology for solving these optimization problems is well established; but algorithm-based vehicle routing is primarily available through subscription-based “software as a service” models developed for large organizations. The Downstream project explores the potential of stand-alone, open source software to support smaller organizations with free or low-cost vehicle routing. FIRST at Blue Ridge is one such small organization: a nonprofit, residential 12-step recovery center in Ridgecrest, NC. FIRST’s clients depend on reliable transportation scheduling to engage with the community, but FIRST’s limited budget and technical staff has prevented them from exploring algorithmic vehicle routing. Downstream is a user friendly, open-source software package that fills the gap revealed by FIRST’s needs. Using the cut-and-branch algorithm devised by Cordeau (2006), Downstream uses linear programming techniques to generate daily transportation schedules optimized to reduce wait time and wear and tear on vehicles. Downstream’s tech stack is accessible for free at a reasonable level of use, including spreadsheet software such as Microsoft Excel, the Google Cloud API and Google’s OR-Tools optimization suite. The software is designed to be easy for a first-time computer user to install and run, with a simple step-by-step installation process. Replacing FIRST’s manual routing process with Downstream saves hours of human effort every week, reduces vehicle mileage, and prevents unnecessary wait times for clients. We hope that other small organizations can reap similar benefits.

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