Pursuant to a legislative requirement, GAO reviewed the Federal Highway Administration (FHwA) new rule on installing reflectors on the sides and rear of semitrailers and trailers. GAO noted that: (1) the new rule requires motor carriers engaged in interstate commerce to install retroreflective tape or reflex reflectors on the sides and rear of semitrailers and trailers that were manufactured prior to December 1, 1993, and meet certain size and weight requirements; and (2) FHwA complied with applicable requirements in promulgating the rule.