Nodding off at the wheel kills almost as many Americans each year as drunk driving

Nodding off at the wheel isn’t just frightening—it can be fatal. Consider that at 55 mph you cover the length of a football field in 5 seconds. In fact, about one-fifth of fatal car crashes involve a drowsy driver, according to a 2014 study from the AAA Foundation for Traffic Safety, in which specially trained investigators analyzed 14,268 car crashes between 2009 and 2013.

To combat that problem, the National Highway Traffic Safety Administration recently initiated a campaign against drowsy driving, and certain states are pursuing legal options. Arkansas and New Jersey allow police to arrest people driving erratically if they admit they’ve been awake for at least 24 hours.

Entrepreneurs have introduced stay-awake gadgets, including an ear device that sounds off if your head nods forward and smartphone apps that randomly blast an alarm. But such devices may only be providing a false sense of security.

Certain cars can now detect driving patterns that suggest drowsiness, such as lane drifting. But what do the high-tech cars do if they think you’re getting sleepy? Mercedes CLA-Class cars turn on a coffee-cup icon and sound an alert. And the navigation system in the Volvo XC90 can direct you to a rest area.

In fact, the best solution is pretty simple, says Nathaniel Watson, M.D., president of the American Academy of Sleep Medicine. Don’t get behind the wheel if you’re tired, and if you find yourself at the wheel struggling to stay awake, change drivers. If you’re alone, pull over somewhere safe and take a nap or get a cup of coffee; note that it can take between 15 minutes and an hour for the caffeine to take full effect.