What safety feature in seats moves forward during a rear impact to reduce whiplash?

The safety feature that moves forward during a rear impact to reduce whiplash is an active head restraint.

Unlike a fixed or manually adjusted head restraint, an active head restraint automatically changes position or geometry when crash forces are detected. In systems such as Saab’s SAHR, the occupant’s torso loads the seatback during a rear-end collision, triggering a mechanical linkage that moves the restraint upward and forward.

This action helps catch the head sooner and reduces the difference in motion between the head and torso. That difference can produce rapid neck extension and flexion, commonly called whiplash. The feature is not an airbag and does not replace a seat belt; it works as part of the seat’s occupant-protection design.

A neighbouring fact often missed is that even a conventional head restraint can be protective when positioned correctly. It should be high enough to support the head and close enough behind it to limit rearward movement. Active designs add automatic crash response, rather than merely providing a permanently fixed cushion.