Background Given equal safety equipment, the rear-center seat is the safest place in a vehicle. However, at this time, lap/shoulder belts are required at all outboard seats, while only lap belts, a less effective device, are required at the rear-center seat. On December 4, 2002, the President signed into law "Anton's Law", P.L. 107-318, which directs NHTSA to issue, by December 2004, a regulation requiring lap/shoulder belts for each rear seating position in passenger motor vehicle with GVWR 10,000 pounds or less. It is anticipated that phase-in would start on September 1, 2005 and all passenger vehicles manufactured after September 1, 2007 would be required to have rear-center lap/shoulder belts, but manufactures are already equipping some of their vehicles with center rear lap/shoulder belts. NHTSA's 1999 evaluation found that rear outboard lap/shoulder belts are 15 percent more effective in reducing fatalities than lap belts alone.

Objectives Estimate the effectiveness of lap/shoulder belts in reducing fatality and injury risk of back center seat occupants - in frontal crashes and overall. Compare the rates of overall injury and serious abdominal injuries of back center seat occupants wearing lap/shoulder belts, lap belts only, and no belts. Compare belt use rates of back center seat occupants in cars equipped with lap/shoulder belts vs. cars equipped with lap belts only. Estimate overall safety benefits of sitting in the back seat, relative to sitting in the front seat of a vehicle. Find out if occupancy of the rear-center seat increases for adults and adolescents when lap/shoulder belts are available, making it the safest place in the vehicle.

Proposed Approach Statistical analyses of FARS and State crash data, by methods similar to those used in the 1999 evaluation of back outboard lap/shoulder belts (e.g., double-pair comparison), to assess the relative fatality and injury risks of lap-belted, lap/shoulder-belted and unrestrained occupants. The evaluation may require several years until sufficient FARS data accumulate.