The objective was to describe at-work and commuting crashes occurring in a cohort of French employees and to investigate occupational risk factors. The subjects were employees of the French national electricity and gas companies, Electricit?e France and Gaz de France (EDF-GDF), who volunteered to join a research cohort (the GAZEL cohort which included 20,625 participants in 1989). Only crashes with injuries were considered. Crashes for the periods 1989-2001 were recorded together with the type of journey (commuting, work, private), the type of road-user, self-estimated responsibility, and injuries sustained by the subject. Annual incidences for gender/age groups and socio-occupational groups were computed for each of the two types of work related crashes. Occupational risk factor analyses were conducted using a Cox proportional hazards regression model with time-dependent covariates adjusting for the main confounders. A total of 146,285 person years at work were observed. Two indicators of self-reported work fatigue were associated with the occurrence of at-work crashes: "nervously tiring work" for males (RR=1.6, 95% CI [1.1; 2.3]), sustained standing for females (RR=3.0, 95% CI [1.0; 8.4]), adjusting for health status, location of residence, type of family, transport mode and mileage. As regards crashes while commuting, a self-reported uncomfortable position at work was a risk factor among women (RR=1.9, 95% CI [1.1; 3.3]). On the other hand, these occupational factors were not linked to road crashes in private trips. Work related road crashes seem then to be a matter for a specific prevention. Preventing employees from becoming exhausted should be considered as the first way to initiate such a prevention.