Rigis seats with 28-inch seatback effetively reduce injuries in 30+ mph rear end impacts.

Findings based on a series of rear-end collision test show that rigid seats of designs very similar to today's bucket seat but unyielding seatbacks at least 20 in. high offer protection in most rear-end collisions. Present productions seats, with an average 21-in. seatback, offer little or no protection against whiplash. The addition of retrofitted restraints is not as effective as the integral seat design. Most vehicle rear seats are already rigid. They require only that seatback height is increased.