This SAE Recommended Practice establishes a method of evaluating the structural integrity of the parking brake system of all new trucks, buses, and combination vehicles designed for roadway use and falling in the following classifications: Tractor, Trailer, truck, and bus: over 4500 kg (10 000 lb) GVWR. The main purpose of the document is to evaluate the structural integrity of a vehicle's parking brake system. However, other areas, such as suspension and drivetrain system, may also be evaluated during the test, provided that the criteria and procedure detailed are not modified in any way.