General Motors optimizes its scheduling of cold-weather tests

The General Motors Cold Weather Development Center is responsible for performing vehicle road tests under excessively cold weather conditions; each vehicle must undergo a specified number of tests under various temperatures in specified sequences. The center usually completes a vehicle's tests over several weeks based on such factors as the number of days cold enough to provide meaningful results. The center prepares a master test schedule daily with the goals of maximizing overall efficiency, assigning enough tests to each vehicle, and respecting operating constraints. To address this scheduling problem, we developed a decision-support tool with a specialized heuristic. Implementing the tool improved throughput by more than 100 percent and saved millions of dollars in vehicle warranty cost.