Learning from Drivers to Tackle the Amazon Last Mile Routing Research Challenge

TL;DR

This paper introduces a hierarchical approach combining machine learning and TSP solvers to improve last-mile routing by learning driver behavior and optimizing route sequences, achieving competitive results in the Amazon challenge.

Contribution

The paper presents a novel hierarchical method that integrates driver experience modeling with traditional TSP algorithms for improved route planning.

Findings

Achieved an evaluation score of 0.0374, comparable to top challenge teams.

Successfully encoded driver know-how through sequential probability modeling.

Demonstrated applicability to diverse routing scenarios beyond the challenge.

Abstract

The goal of the Amazon Last Mile Routing Research Challenge is to integrate the real-life experience of Amazon drivers into the solution of optimal route planning and optimization. This paper presents our method that tackles this challenge by hierarchically combining machine learning and conventional Traveling Salesperson Problem (TSP) solvers. Our method reaps the benefits from both worlds. On the one hand, our method encodes driver know-how by learning a sequential probability model from historical routes at the zone level, where each zone contains a few parcel stops. It then uses a single step policy iteration method, known as the Rollout algorithm, to generate plausible zone sequences sampled from the learned probability model. On the other hand, our method utilizes proven methods developed in the rich TSP literature to sequence stops within each zone efficiently. The outcome of such a combination appeared to be promising. Our method obtained an evaluation score of $0.0374$, which is comparable to what the top three teams have achieved on the official Challenge leaderboard. Moreover, our learning-based method is applicable to driving routes that may exhibit distinct sequential patterns beyond the scope of this Challenge. The source code of our method is publicly available at https://github.com/aws-samples/amazon-sagemaker-amazon-routing-challenge-sol