Pursuant to a congressional request, GAO evaluated the National Highway Traffic Safety Administration's (NHTSA) state motor vehicle inspection program, to determine whether: (1) a 1989 NHTSA report accurately represented the safety benefits of state inspection programs; (2) available evidence indicates that state inspection programs reduce accidents; and (3) NHTSA appropriately carried out its responsibilities regarding inspection programs. GAO found that: (1) periodic inspection programs improve the condition of the safety-related components of vehicles subject to inspection; (2) accidents involving vehicle defects occur less often in states requiring periodic inspections; (3) state periodic inspection programs reduce the number of poorly maintained vehicles; (4) NHTSA issued a standard requiring states to inspect vehicles at least annually, and in 1973 issued specific standards for vehicle inspection; and (5) NHTSA intends to resume supporting periodic vehicle inspections.