A study by the Insurance Institute for Highway Safety in the US has found that the Saab Active Head Restraint (SAHR) significantly reduces neck injuries in rear-end collisions. According to the study, SAHR provided a 43% reduction in neck injury claims, including a 55% reduction in claim rates for women and a 31% reduction for menThe study measured the effectiveness of the SAHR system - which provides active, anti-whiplash head restraint and is standard equipment in all Saab models - by comparing the rates of insurance claims for driver neck injuries in rear-end crashes before and after the SAHR system was first introduced in 1997.In another study released in the US last year by the Journal of Trauma, the SAHR system was determined to reduce the risk of neck injuries relating to whiplash in rear-end collisions by as much as 75 per cent. Real-life crash statistics show that neck injuries are one of the most common results of rear-end collisions, even at relatively low speeds. The triggering factor in these whiplash injuries is the violent movement of the head in relation to the body during an impact from behind, often leaving victims with long-term pain. In the event of a rear-end collision, the SAHR system is designed to limit the head movement of the occupant during the impact, helping to reduce the risk of whiplash injuries. The system is entirely mechanical and is based on the lever principle. An upper padded support is connected to a pressure plate in the backrest of the seat. In some rear collisions, the occupant's body will be forced by the crash pulse into the backrest, which moves the pressure plate towards the rear. Subsequently, the head restraint is moved up and forward to "catch" the occupant's head before the whiplash movement can start. The precise activation of the system is determined by the force with which the occupant's back is forced against the backrest, the magnitude of the collision forces and by the occupant's weight.A benefit of the mechanical SAHR system is that in most crashes it needs no repairs to restore it to operational condition after it has been activated. The head restraint automatically reverts to its initial position and is immediately ready to operate again. As whiplash injuries usually occur in low-speed collisions in which the vehicle may sustain only limited damage, the active head restraint does not increase the cost of the repairs needed after the crash.Saab's new 2003 9-3 Sport Sedan features a "second generation" SAHR for even faster activation in rear impacts at lower speeds. The head restraint is activated as soon as the lower back is pressed into the seatback by the occupant's inertia during a rear impact.