Morbidly obese drivers have a higher risk of road crashes because of associated conditions such as obstructive sleep apnea. We assessed whether weight loss surgery has an impact on subsequent road crash risks in morbidly obese drivers. Our longitudinal self-matched cohort analyses suggest that road crash risks are three times higher in morbidly obese drivers than the population norm. Yet, weight loss surgery yields no significant reductions in crash risks. We found similar results in patients not previously diagnosed with sleep disorders, suggesting the need to clarify the relationship of obesity with road crash risk.