Field study accident data were analyzed in order to investigate some aspects of side impacts concerning the restrained occupant seated on the non-struck side. Seat belt performance was assessed in this situation for which they are not primarily designed. 7.7% of restrained occupants were exposed to this type of accident situation. The vehicle damage pattern and impacting object were described. Most (80%) injury 2 AIS 3 occurred when the passenger compartment intrusion exceeded 20 cm. A speed change ≤ 35 km/h was usually consistent with intrusion below that level. Injury causing contacts were assigned to many injuries so that it was possible to assess the role played by the far side structures, another occupant between case occupant and far side, and seat belt. Thus occupant egress from the seat belt diagonal was found to have occurred in 35% of cases. The head and face were particularly vulnerable, and chest injury was commonly caused by the seat belt. Also the lap section of seat belts posed a potential threat to the abdomen. An occupant beside proved to be a positive benefit in many cases showing that occupant interaction is an important consideration during crash simulation. Further consideration of seat belt design and supplementary technology are recommended.