In the New Car Assessment Program (NCAP), beginning with the model year 1994 vehicles, the National Highway Traffic Safety Administration (NHTSA) developed and adopted a simplified nonnumeric format for presenting the comparative frontal crashworthiness safety information to consumers. This paper presents the basis for the development of this “star rating” system. The injury probability functions which are used for the star rating system are also applied to the results of the recent NCAP real-world correlation studies and a review of these studies is given.The safety performance for restrained occupants as measured in NCAP is dependent on several parameters which include: the design of the restraint system, the maintenance of the integrity of the occupant space, and the energy management performance of the front structure. There have always been some concerns that in designing for “Lower Risk” performance in the 35 mph NCAP tests, energy management structures could be improperly designed for other frontal crash conditions and crash severities. This point is discussed and structural parameters of “Lower Risk” and “Higher Risk” passenger cars, light trucks, vans, and sport utility vehicles are compared.