A study was undertaken to examine the relationship between safety belt usage by drivers and risk taking as measured by running red lights. At two urban intersections, observations were made of shoulder belt use and of whether cars went through red lights. During 70% of the light changes observed, at least one driver went through a red light. Of the drivers who went through red lights, only 1% were wearing shoulder belts, compared with 8% of the other cars. The association between risk taking and extremely low seat belt use underscores the importance of incorporating automatic crash protection into automobile design.