If you've ever watched a car drifting across lanes or weaving erratically, you probably wondered if the driver was under the influence. There are many causes for bad driving, and alcohol is prominent among them. Another possibility, however, is that the driver is sleep deprived. A report from the AAA Foundation for Traffic Safety shows that fatigue creates a similar risk profile in a driver to that of overindulging in alcohol.
Too little sleep
According to the Centers for Disease Control and Prevention, more than a third of all Americans are sleep-deprived. The average adult needs 7 hours of sleep per night. Approximately 35 percent of people do not reach that figure. Around 12 percent get 5 hours of sleep or less. That is not enough to safely operate a motor vehicle.
The comparison to drunk driving
There is a sliding scale of risk when it comes to drunk driving. Even small amounts of alcohol increase the risk of a car accident. The odds of a crash rise steadily from a BAC of .02 to the legal limit (in most cases) of .08. The crash rate worsens rapidly beyond that point. There is a similar trend when it comes to driving without sleep. Drivers who got between 6 and 7 hours of sleep faced an increase crash risk of 1.3 percent. At 5-7 hours, it was 1.9. From 4-5 hours, the increase was 4.3 percent. Drivers with less than 4 hours of sleep in the past 24 were 11.5 percent more likely to get into a car accident. The report concluded that driving with less than 4 hours of sleep equated to driving with a BAC of between .12 and .15, well beyond the legal limit anywhere in the U.S.
Another similarity to drunk driving is that many people exhibit an overconfidence about their abilities. Sleep-deprivation and alcohol affect everyone. Driving drunk and not getting into an accident is luck, not skill. Likewise, fatigued driving is not a skill. A driver may escape without harm many times before the odds catch up. Whether it is the first time or the 100th, if you are driving after too little sleep, you are putting yourself and everyone around you in danger.
Source: The Washington Post, "Sleep-deprived drivers have plenty in common with drunk drivers," by Ashley Halsey III, 6 December 2016