The effect on occupant restraint use and effectiveness is evaluated with regard to General Motors (GM) introduction of the "comfort feature" into the front outboard seating positions on most of its automotive fleet during model years 1976-79. The device allows front seat occupants to pull a small amount of additional belt webbing from the retractor, which will then stay in the extended position. This removes the shoulder pressure caused by the spring tension in the retractor, and is intended to increase operator comfort. Using a matched pair analysis technique on model pairs formed by the model year before and of comfort feature introduction revealed a statistically significant increase in seat belt use by accident involved outboard front seat occupants involved in accidents in the states of Michigan, Texas, Washington and Ohio. Restraint use increased from 17 percent in Michigan to 25 percent in Texas in comfort-feature-equipped vehicles when compared with restraint use in previous model year vehicles in the accident data from the four states. More than 200,000 accident reports were compared for vehicles in the same accident years, 1982-85. The analysis was repeated on the NHTSA 19-City Restraint System Usage Survey data for 1984-86 and the same increase in belt use was observed in comfort-feature-equipped vehicles. Examination of accident injury data revealed no detectable change in the effectiveness of the front outboard occupant-restraint system, so the observed increase in restraint usage translates into a national estimate of more than a thousand serious and fatal injuries being prevented annually through increased restraint use in comfort-feature-equipped GM vehicles.