The actual threat posed by unrestrained rear seat car passengers.

A statistical analysis of the threat posed by unrestrained rear seat car passengers to restrained drivers and front seat passengers was published in 2002. This was based on Japanese accident data from 1995 to 1999, and the conclusions have been checked using corresponding accident data from Great Britain. The law in respect of the use of seat belts and other restraint systems was less strict in Japan than in Great Britain between 1995 and 1999, so an earlier period had to be studied. The results suggest that the risk of death to a front seat car occupant is increased by about three-quarters by the presence of an unrestrained rear seat passenger behind them, a much smaller increase than was claimed by the Japanese researchers.