Wheel chocks are wedges of sturdy material placed against a vehicle's wheels to prevent trucks from rolling accidentally. Made from rubber, plastic or polyurethane, wheel chocks are used as an additional safety device, along with the brakes of the truck. They are often used when a truck is parked at an inclined surface or during loading/unloading. Wheel chocks reduce the risk of damage to surrounding areas as they prevent accidental movements of vehicles.