Automobile accidents occurred with 55% of seizures in epileptic drivers with both well-described seizures at the wheel and a well-classified epilepsy diagnosis. A further 38% of seizures would have led to accidents in less fortunate settings. Complex partial seizures occurred in 81% of patients and were responsible for 88% of accidents. Immediate alterations of consciousness were significantly more likely to lead to accidents than were seizures beginning with an aura. Motor activity during simple partial seizures was also responsible for some accidents. Differences in seizure frequency may account for different crude accident rates among studies of epileptic drivers. We suggest guidelines for licensing restrictions that seem safe and reasonable.