We're all well aware of how risky it is to drive under the influence of alcohol or drugs -- so much so that we sometimes forget it took a public campaign like Mothers Against Drunk Driving in 1980 to promote laws across the country cracking down on it.
But there's one kind of impaired driving that is a much grayer area, both for lawmakers and for drivers themselves: driving while sleep-deprived.
Sleep deprivation has severe effects on performance. Staying awake for 24 hours is equivalent to having a BAC of 0.08 percent, which is legally drunk.
Calculating the number of accidents attributable to drowsy driving can be difficult. The National Sleep Foundation suggests that drowsy driving is linked to about 100,000 car crashes every year. The National Highway Traffic Safety Administration determined the average number of accidents linked to sleep deprivation between 2005 and 2009 to be about 83,000 per year. Studies by the American Automobile Association, however, estimate that more than 300,000 accidents each year involve a drowsy driver, with 6,400 resulting in someone's death.
Despite these numbers, only two states in the U.S. have any laws against "drowsy driving," and even these are largely symbolic and tough to enforce.
"The burden of proof in drowsy driving cases falls almost totally on police officers," Jeff Evans, program manager of the National Sleep Foundation, told The Huffington Post. "Barring a confession from the accused driver, it is very difficult to prove that someone was sleep-deprived."
New Jersey became the first state to pass drowsy driving legislation in 2003 with "Maggie's Law," which says that if a driver kills someone after not sleeping for more than 24 hours, the driver can be charged with vehicular homicide.
The law was the result of a campaign by Carole McDonnell, whose daughter Maggie was killed in a 1997 car crash by a van driver who had smoked crack and hadn't slept in 30 hours. The driver got off with a $200 fine because the jury could not consider driver fatigue as a factor of guilt.
But the law is tough to enforce. It requires the driver to admit sleeplessness in court, and there's no test yet to prove someone is sleep-deprived. In the decade since the law's passage, only one person has been prosecuted under it for driving while fatigued.
New Jersey's law got renewed attention in 2014, when comedian Tracy Morgan was seriously injured on the Jersey Turnpike when a truck driver who hadn't slept in 28 hours crashed into Morgan's limo. The crash killed one passenger and sent Morgan into a coma. Under Maggie's Law, the driver was indicted for vehicular homicide for reckless driving.
New Jersey State Senate President Stephen Sweeney released a statement after Morgan's crash reiterating the importance of Maggie's Law. "When people go without sleep and get behind the wheel, they are putting their lives and the lives of everyone they encounter on the road in danger," he said.
In 2013, Arkansas passed a similar law that allows the state to charge a driver with "negligent homicide" in a fatal crash if the driver hasn't slept in 24 hours.
How could the laws be better?
At the moment, the issue of drowsy driving lacks the strong public advocates that drunk driving had. Mothers Against Drunk Driving helped reduce alcohol-related accidents dramatically in the 1980s, and in the 1990s, Harvard public health professor Jay Winsten led a national "designated driver" campaign to popularize one possible solution for the drunk driving crisis. Both these efforts elevated the problem of drunk driving in the American public consciousness.
The groups paying attention to drowsy driving have a range of opinions on how best to address the problem, and not all of them include legislation.
Bill Windsor, Nationwide Insurance's assistant vice president of consumer safety, told HuffPost in an email that he was frankly "not sure how to effectively legislate for this problem for non-commercial drivers."
And Douglas Horn, a Kansas City lawyer who specializes in motor vehicle accident law, flatly stated, "I am not in favor of legislation."
"To my way of thinking, there is not an effective way to reduce driver fatigue through laws," Horn told HuffPost in an email.
The National Sleep Foundation, on the other hand, firmly advocates for more and broader laws against drowsy driving. NSF is an independent nonprofit that promotes sleep education for public health and supports sleep research.
"Let's be clear," NSF's Jeff Evans told HuffPost, "any law is better than no law. Even if it comes to use only in the extreme case of vehicular homicide."
The problem is that the current laws are nearly impossible to enforce, and place "undue pressure on a police officer" to prove 24 hours of wakefulness, said Evans.
He suggested replacing the 24-hour threshold with a new "two-hour standard," citing an NSF report released last November that concluded that "drivers who have slept for two hours or less in the preceding 24 hours" are definitely too tired to drive. That would be a better baseline measure and make it easier to convict dangerously drowsy drivers, he suggested.
Any state looking to legislate drowsy driving has a few other concerns to address. It is a labor issue, for starters: People who work multiple jobs, engage in shift work or have long commutes have real constraints on their lifestyle choices. If they are to change their sleep behavior, their employers must play a part as well.
Moreover, do sleep disorders constitute reckless behavior in the context of driving? Should someone suffering from chronic insomnia or sleep apnea face the same standard as someone who used drugs, or who knowingly stayed awake too long?
And of course, the reach of a particular law may be small, but its impact on public consciousness can be much larger. This seems to have been the case with laws against texting while driving, which have had a public impact larger than their number of prosecutions. A 2014 study found that states with texting bans had 3 percent fewer traffic fatalities across the board.
"What we really need to reduce the number of drowsy driving accidents is for lots of people to starting talking about it -- and thinking about it," says Evans. "Laws are one of our many tools with which to do that."
CORRECTION: A previous version of this article misstated the minimum BAC to be considered legally drunk as 0.05. In all states, it is 0.08. This article has been updated with additional statistics related to drowsy driving accidents.