This SAE Recommended Practice establishes for left-hand steer on-road trucks, buses, and multipurpose passenger vehicles with GVW of 4500 kg (10 000 lb) or greater: a. Minimum performance requirements for windshield wiping systems. b. Uniform test procedures that include those tests that can be conducted on uniform test equipment by commercially available laboratory facilities. c. Uniform terminology of windshield wiper system characteristics and phenomena consistent with those found in guides for the use of engineering layout studies to evaluate system performance. d. Guides for the design and location of components of the systems for function, servicing of the system, etc. The test procedures and minimum performance requirements, outlined in this document, are based on currently available engineering data. It is the intent that all portions of the document will be periodically reviewed and revised as additional data regarding windshield wiping system performance are developed.