Federal motor vehicle safety standards required installation of passive restraints in passenger vehicles beginning with the 1987 model year. Manufacturers met standards by using either "automatic" seatbelt systems or airbags with active (manual) seat-belt sys-tems. Several different automatic designs were employed.
This paper addresses accident performance of various automatic seat-belt systems and discusses (1) factors that influence belted injury rates and (2) statistical procedures used to control for these factors. Different automatic systems are described and a list of passenger vehicles with different automatic systems is presented. State motor vehicle accident data were examined to assess the overall safety performance of automatic belts. Performance comparisons were made after controlling for factors that might influence injury rates, including (1) vehicular factors such as vehicle size and body style; (2) accident factors such as single- versus multiple-vehicle accident, rollover, and accident severity; and (3) driver-related factors such as driver age. Injury rates for belted and unbelted front-seat outboard occupants and the percentage reduction in injury for belted front-seat outboard occupants are reported as measures of overall belt effectiveness.
The analyses show no consistent significant difference in safety performance among various types of automatic restraint systems.