While there may be some tasks you can perform safely when you’re feeling drowsy, you should know that driving is not one of them. Driving while drowsy may sound harmless, but being sleepy behind the wheel can have dangerous effects on your driving even if you don’t fall asleep.

Of course, any adult driver is vulnerable to the effects of drowsiness if they don’t get the recommended hours of rest each night. Driving fatigued makes you three times more likely to be in a crash. However, some drivers on the road have a higher likelihood of driving drowsy than others. Below are some of the most common risk factors that cause people to drive while drowsy:

Undiagnosed sleep disorders

If you sleep eight or more hours a night but still find that you frequently feel tired, you may have an untreated sleep disorder like sleep apnea, which causes side effects like daytime sleepiness. Other conditions, like narcolepsy, will cause a person to fall asleep suddenly. If these symptoms sound familiar, be sure to discuss your concerns with your doctor right away.

Age and gender

According to the National Safety Council, drivers under 25 make up roughly 50% or more of all drowsy driving collisions. Males in this age group were particularly at risk of getting into an accident. Young men must get enough sleep each night and avoid getting behind the wheel if they feel too drowsy.

Medications

Countless drugs can cause drowsiness as a side effect, even over-the-counter medications. If you’re taking a new medication, always be sure to discuss its side effects with your doctor or read the label carefully before you operate a motor vehicle.

Shift workers

Those who work long hours and night shifts are especially vulnerable to drowsiness on their way home from work. Truck drivers, police officers, nurses or doctors are all common careers that involve late nights, lengthy shifts or both. If you are a shift worker, be sure you feel alert and awake enough to drive before heading home.

While anyone can experience drowsiness behind the wheel, specific individuals can be at higher risk than others. At the very least, getting plenty of sleep each night can help you avoid the dangers of driving drowsy this fall.