Most Americans think getting behind the wheel drowsy isn’t a big deal. In a culture that’s always working and on-the-go, it’s no surprise that nearly half of adult drivers admit to frequently driving while fatigued. However, driving drowsy isn’t as harmless as you might believe. According to a study by the AAA Foundation for Traffic Safety, an estimated 328,000 drowsy driving accidents occur every year.

Before you get behind the wheel after a poor night of sleep, it’s important to remember that driving drowsy is dangerous and can have fatal consequences. Here are some of the most common myths surrounding driving and sleepiness and the facts behind them:

Myth: You can prevent drowsy driving with caffeine 

While caffeine comes in countless different forms and increases alertness, it will never be a substitute for sleep. For most people, caffeine takes about 30 minutes to kick in. If you consume caffeine regularly, it likely won’t have much effect. If you’re seriously sleep-deprived and consume caffeine, it’s still possible to fall asleep behind the wheel. Even if it’s only for a few seconds, it’s plenty of time for a crash.

Myth: You don’t need that much sleep

You might think you can get by just fine without a good night of sleep, but the research says otherwise when it comes to driving. Most adults need about eight hours of sleep per night to function optimally. The less sleep you get, the more it impairs your driving abilities and judgment. Getting less than six hours of sleep at night makes you three times more likely to get into a collision.

Myth: You can tell when you’re going to fall asleep

Many people believe that they can tell when they’re too sleepy to drive, but sleep is a powerful force. You might think you can make yourself to stay awake, but your body might have other plans if you aren’t well-rested. Drivers can easily fall asleep behind the wheel and not know it, especially if they are driving late at night.

The importance of a good night’s sleep cannot be understated for staying awake and alert on the roads. Don’t let these mistruths about sleep keep you from getting the rest you need to drive safely.