Three point safety belts are intended to restrain front seat occupants in motor vehicle crashes. Their purpose is to reduce the severity of occupant collisions with the interior of a vehicle and thus to reduce occupant injury. Manufacturers and the government test occupant protection in frontal collisions both for compliance with federal requirements and under a federal consumer information program. No consensus exists for a test of the ability of seat belts to prevent harmful contact with the roof and roof structure of vehicles. This paper describes a simple test procedure and provides data from tests of some common production safety belt systems. These tests demonstrate that most of the production belts place the head and neck in potentially injurious positions in a rollover. These tests also show that simple geometric improvements could provide substantial head and neck protection in rollover crashes.