The state lists sleep apena under head injuries and seizure disorders as conditions that impair drivers. So to renew or get a license you have to produce the sleep study that diagnosed the ailment and two years of usage logs of the CPAP.

It's a matter of public safety. Driving while sleep deprived significantly increases the odds of crashing your car, and sleep apnea can in some cases deprive you a lot. A colleague of mine fell asleep behind the wheel on his morning drive to work, totalled his car. Turned out he had sleep apnea.