A recent study shows that obese drivers are more likely to die in car crashes than non-obese drivers. The reason(s) for this are unclear at this time, but this article discusses several possible explanations. Including vehicle design and the underlying poorer health of the obese. I suspect that another factor may be at play: sleep apnea.
We know that obesity is a key factor in sleep apnea. We know that people with sleep apnea experience increased daytime sleepiness. We know that sleepy drivers exhibit levels of impairment comparable to drunk drivers. I believe that at least some of the increased risk of mortality for obese drivers is attributable to sleep apnea, and that this is simply one more public health implication of the growing prevalence of both obesity and apnea in the United States.