This paper reports on how front seat passengers and drivers sit in cars relative to the frontal structures of the vehicle interior. Car occupants were filmed unobtrusively in the general traffic flow in the United States and in the United Kingdom. The results highlight specific subgroups of the driver population more likely to sustain injury in a frontal collision. The international comparability of these results, together with the evidence of wide variation in sitting positions paves the way for 'smart' restraint systems which could effectively address the safety of a wider cross section of the occupant population.