Seat belt use in the United States has reached a high of 90.4 percent according to a recent government survey¹. There has been a steady increase in seat belt usage in this country as a result of individual state mandatory use laws, as well as an increased awareness and knowledge of crashworthiness and safety issues by the motoring public in general. The need to restrain occupants within vehicles to provide protection during crashes has been well known for many years in the occupant crash protection area in general, and in the automobile industry in particular. It has also been the subject of numerous public safety campaigns and advertisements. Occupant crash protection has traditionally been provided through the use of seat belts. In a vehicle crash, the purpose of a seat belt is threefold:²
- To prevent occupant ejection from the vehicle;
- To couple the occupant to the vehicle and thus take advantage of the energy management properties provided by the crush of the vehicle’s structure, thereby allowing the occupant to “ride down” the forces produced during the crash; and
- To minimize or eliminate the “second collision” of the occupant against the interior surfaces of the vehicle.
By preventing or minimizing the impact of the “second collision,” the forces applied to the occupants are controlled or reduced and, by properly distributing the crash forces to the strong bony portions of the body, the potential and severity of any injuries to the occupant can be minimized or eliminated.