Gathering that data might be difficult, as well.
Drunk driving isn't the only kind of impaired driving. Anything that affects your coordination, attention, and response time can be considered impairing, including being tired. In fact, driving drowsy can present many of the same effects as driving drunk. It's a wonder why nobody is concerned about it, then. Oh, wait ... the National Highway Traffic Safety Administration (NHTSA) is very concerned about it, and it wants the public to be, too. The only trouble is an lack of supporting data.