This SAE Recommended Practice provides a field test procedure and instructions for: a. instrumentation and equipment; b. vehicle preparation; c. test of air-braked single and combination vehicles; d. calculation of brake force distribution; and e. this test procedure is intended to be used as a field procedure. If a more refined method, utilizing laboratory equipment, is required, refer to SAE J1505.

This procedure provides a method to determine the brake force distribution (brake system effectiveness) for trucks and buses with a GVWR greater than 4536 kg (10 000 lb).