STUDY OBJECTIVE: We conducted a longitudinal investigation of the impact of self-reported life events and medical conditions on changes in road mobility on the wheel between 2000 and 2002 in order to assess whether these changes would affect the risk of road traffic accident (RTA). METHODS: Data are from a cohort of workers and retirees from the French national gas and electricity companies (the Gazel cohort). In the present study, 10,483 participants were included (7843 men aged 51-61 years and 2640 women aged 46-61 years, in 2000). The link between mobility and the risk of RTA was approximated using data on RTA number during lifetime and reported mobility in 2000. We then compared changes in road mobility between 2000 and 2002 resulting from life events and medical conditions reported to have occurred in the year 2001 or changed when compared to year 2000. We also compared road mobilities in 2000 in order to assess any pre-existing differences before life events and medical conditions. This led to estimation of the effect of road mobility changes on the risk of RTA. RESULTS: Changes in road mobility associated with life events and medical conditions were only found among men. These changes in road mobility were minimal. Ensuing changes in the risk of RTA were estimated to be small (odds-ratios ranged from 0.94 to 1.01). The only life events found to be associated with increased road mobility was an important purchase. Hospitalization, serious RTA, and retiring were associated with reduced road mobility. Concerning medical conditions, men who reported cataract, angina pectoris, diabetes, anxiety and stress, sleep disorder, and depression decreased their road mobility. CONCLUSION: We found no or moderate changes in road mobility resulting from life events and medical conditions, suggesting that results from previous published studies that assessed the impact of life events or medical conditions on RTA were not jeopardized by improper adjustment for road mobility.