In reality most headrests provide little to no protection. European automobiles rate far better than domestic or Asian models in this area. The federal government required their installation in 1967, but haven't provided standards for their successful implementation. An effective headrest is directly behind the centerline of the head and positioned no more than a couple of inches away. Be aware that some seating options change the size and style of head restraint.
Structural integrity is another important component of passive safety.
In the past few years significant accident-avoidance and safety systems have been introduced on many automobiles. ABS brakes, traction control, electronic stability control, night vision, and automatic cruise control are some of the electronic miracles that assist modern drivers today. However, a small number of accidents are unavoidable no matter how skilled a driver may be. Recent deadly 100-car pileups in the United States, Sweden, Great Britain, Italy, and Germany demonstrate that crash survivability must not be taken for granted. Tires are the most important safety item on a car.