• The 1974 and early-1975 model automobiles are equipped with belt interlock systems that require front outboard seat occupants who weigh more than 21.5 kg (47.3 lb) to wear three-point lap and diagonal upper-torso belts (or wear the lap belt and position upper-torso belt behind them), assuming that the interlock has not been circumvented. Recent legislation has eliminated the interlock requirement, but new models are still likely to be fitted with three-point restraints for the front outboard seating positions.
These restraint systems were designed and tested for adult use. Thus, based on the different structure of a younger child and the fact that there is a wide variation of belt orientation, child size, and seating environments, there is legitimate concern that the upper diagonal belt might contribute to injury of the child under certain impact conditions.
(Am J Dis Child 129:946-949, 1975)