The small proportion of rear seat occupants, and the small proportion of those who use lap belts, make accumulation of sufficient reliable data on rear seat lap belted accident victims difficult. Existing studies have produced a wide variety of effectiveness estimates. The National Transportation Safety Board reported the outcomes of 30 crashes, predominantly frontal, involving unrestrained, lap/shoulder belted, and lap belted occupants (mainly rear seat). The Board recommended rear seat lap/shoulder belts for new cars, retrofit assemblies for existing models, and improved training of emergency care providers in diagnosis and handling of belt-induced trauma.
