This standard applies to all passenger cars, and to trucks and multipurpose passenger vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less. However, it does not apply to walk-in van-type vehicles. Additionally, paragraph S5.3 of this standard applies to all motor vehicles, except trailers and motorcycles, with a GVWR of 4,536 kilograms (10,000 pounds) or less.