In 1967, a breakthrough occurred in the development of airbag crash sensors, when Allen K. Breed invented a mechanically-based ball-in-tube component for crash detection, an electromechanical sensor with a steel ball attached to a tube by a magnet that would inflate an airbag in under 30 milliseconds [REF].
In 1974, GM made its "Air Cushion Restraint System" (ACRS) available as a regular production option (RPO code AR3) in full-size Cadillacs,[REF] Buick and Oldsmobile models.