This paper examines the engineering and economic feasibility of inflatable restraint systems and structural modifications required to achieve passive protection for occupants in passenger car frontal collisions at 50 mph equivalent barrier speed. Vehicle structural modifications, already proved in prototype tests, are examined for compatibility in car-to-car crashes. The special aspects of inflatable restraint systems capable of 50 mph protection are also discussed, taking into account the improvements in system behavior made possible by structural modifications. Costs and benefits are also projected. It is concluded that cost-effective 50 mph protection can be achieved.