Building and racing mousetrap cars is a common activity in many eighth- and ninth-grade physical science classrooms. However, once students have raced their cars, most mousetrap assignments come to an end. The project described here was developed to help teachers get more mileage out of mousetrap cars. The project enables students to investigate the physics behind car construction and performance and is completed in four stages: assembly and materials, the race, data collection for the laboratory, and a final assignment that includes a to-scale diagram of the car and reflective essay.