Determining System Trailer Fleet Size and Terminal Assignment

Abstract

Saia, Inc. is a super-regional, less-than-truckload (LTL) company. The team developed an approach to optimize the composition of Saia's trailer fleet, and to assign the fleet to appropriate terminals throughout the network. The approach relies on a large-scale integer program that models the flow of trailers of different types over time using a week-long planning horizon across Saia's network of nearly 150 terminals. Using the model for a number of planning weeks, the approach is used to determine the right size and composition of the trailer fleet and provides a purchasing strategy given a capital budget for new trailers. It is estimated that Saia will save $1.8 million annually using the fleet proposed by the approach.