Falling asleep while driving or drowsy driving (driving while feeling sleepy) can be disastrous for you, your passengers, and anyone else on the road. Even if you don’t fall asleep behind the wheel, driving while sleepy can lower your focus, reaction times, and decision-making skills, all of which can lead to fatal accidents.
Before we scare you silly, though, there are ways to prevent drowsy driving and ways to perk yourself up when you’ve got a long drive ahead.
Below, we’ll dive into why you’re falling asleep while driving and how you can use the RISE app to stop it from happening.
“Falling asleep while driving can be life-threatening, so it’s important to get enough sleep each night, says Dr. Chester Wu. "To make it easier to fall asleep, try spending time in sunlight first thing in the morning, exercising during the day, and avoiding light in the evenings.”
Dr. Chester Wu is double board certified in Psychiatry and Sleep Medicine, and provides sleep medicine services, medication management, and psychotherapy to adults at his private sleep medicine and psychiatry practice.
Drowsy driving is exactly what it sounds like: driving while drowsy. You might feel sleepy, keep yawning, struggle to keep your eyes open, and you may even fall asleep behind the wheel.
Drowsy driving can therefore easily cause a car accident. Your focus, decision-making skills, and reaction times are all lowered. And driving while sleepy can cause microsleeps — or dozing off for a few seconds.
When you're cruising at 65 miles per hour on a highway, those seconds can mean life or death. Nodding off for merely three seconds is enough for your car to travel nearly the length of a football field, plenty of distance for a fatal crash upon impact. Understandably, sleep-related vehicle accidents account for an excessive amount of rear-end and head-on collisions.
And most worryingly, it doesn’t take much sleep loss to affect your driving. A 2022 study found a single night of mild sleep deprivation can lead to more sleepiness, taking longer to brake, and more crashes. These results were seen after sleeping for five hours, something that’s not too uncommon, especially during the workweek.
Falling asleep while driving is, unfortunately, common. According to a 2022 survey from the National Sleep Foundation, 62% of Americans have driven a car when they were so tired they struggled to keep their eyes open. And 37 million motorists are thought to drive drowsy at least once a year.
A 2020 survey from the AAA Foundation for Traffic Safety found about 96% of drivers agreed drowsy driving was very dangerous. But about 24% admitted to being so tired driving they struggled to keep their eyes open at least once in the past 30 days.
And a 2022 survey found 30% of nurses have dozed off during their commute to work, while almost 45% say they’ve felt unsafe or uncomfortable during their commute due to drowsiness.
All this drowsy driving leads to accidents. A report from the Centers for Disease Control and Prevention (CDC) shared:
The effects of drowsy driving go beyond road safety and fatalities, though. In another report, fatigue-related crashes ending in injury or death cost society $109 billion each year (excluding property damage).
Thankfully, work is starting to be done on tackling the issue of drowsy driving. Sleep and fatigue expert Dr. Mark Rosekind (incidentally a sleep science advisor at Rise Science) led the National Highway Traffic Safety Administration (NHTSA) under the Obama administration to carve a new direction for lowering the incident rate of drowsy driving crashes.
By late 2016, the NHTSA had developed and carried out multiple initiatives under the Drowsy Driving Research and Program Plan. With Dr. Rosekind's robust background in fatigue countermeasures, this has translated to increased awareness of sleep deprivation and driving.
The warning signs of drowsy driving include:
There may soon be tests to detect drowsy driving. Machine learning may be used to find out whether a driver is sleep deprived or not from a blood sample. But this kind of test will only be useful if it can help prevent accidents from happening in the first place.
Research from 2022 says one solution would be a car that can detect drowsy driving and autonomously drive to the nearest parking spot.
Until we all have that technology, though, watch out for the symptoms of drowsy driving. If you experience any of these symptoms, pull over and rest or let someone else take the wheel. It’s always better to be safe than sorry.
You probably get sleepy while driving because you’re sleep deprived, driving during a natural dip in your energy levels, have a medical condition, have side effects from medication, or have had alcohol.
Here's a closer look at the common causes of drowsy driving.
If you’re sleep deprived, you’re obviously going to feel sleepy. But you don’t need to have pulled an all-nighter to feel the effects of a lack of sleep behind the wheel. Missing one to two hours of sleep can also cause drowsy driving, as can staying up later than usual to do a late-night drive.
The key term to know here is sleep debt. Sleep debt is the amount of sleep you owe your body. It’s measured against your sleep need, which is the genetically determined amount of sleep you need.
The more sleep debt you have, the more likely you’ll feel sleepy behind the wheel. The AAA Foundation for Traffic Safety found that drivers with less than seven hours of sleep dramatically increase their chances of a collision.
Sleeping for five to six hours almost doubles your likelihood of crashing compared to those who sleep for seven hours or more. Most worryingly, only sleeping for four hours or less increases those odds by 11-fold.
The risks are even higher if you regularly operate your vehicle when feeling lethargic. Habitually sleepy drivers (defined as those who are on the verge of falling asleep at least once in every three times they drive on a highway) are 10 times more likely to crash their vehicles than non-sleepy motorists.
And sleep debt impacts driving so much that it’s on par with drunk driving. One study found if you go about 18 hours without sleep, you’ll suffer the same cognitive impairment as if you had a blood alcohol level of 0.05%.
When you’ve gone 18 to 20 hours without sleep (perhaps by staying up two to four hours later than usual) is similar to having a blood alcohol level of 0.1% — over the legal limit for driving in every state.
To find out if sleep debt is behind your drowsy driving, use RISE to find out your individual sleep need and how much sleep debt you have. The more sleep debt you have, the more likely you’re going to feel drowsy while driving.
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Your circadian rhythm is your body’s internal body clock. It dictates when you feel sleepy and when you feel alert over a roughly 24-hour cycle.
There are times of day when your energy levels will be lower than other times. These include:
These dips in energy will happen even if you’ve had enough sleep, but they can feel worse if you’ve got a lot of sleep debt.
And these energy dips can easily happen when you’re behind the wheel. A national survey highlighted that about 35% of drowsy drivers nodded off at the wheel between the early morning and late afternoon. And according to the Department of Health of New York State, most sleep-related crashes occur between 1 p.m. and 4 p.m. (around the time of the afternoon dip for most people) and 2 a.m. and 6 a.m.
Plus, if you’re living out of sync with your circadian rhythm, you’ll be left low on energy at any time of day — not a good thing for drivers.
You may be out of sync with your circadian rhythm if:
You’ve probably felt the effects of your circadian rhythm at work (most likely around 1 p.m. to 3 p.m. when the afternoon slump hits), but it can be hard to know how long this dip in energy will last. To help, RISE predicts the timing of your circadian rhythm each day. You’ll then see when your energy levels will most likely rise and fall over 24 hours, and therefore when you’ll most likely feel sleepy if you drive.
Sleep disorders can make it hard to meet your sleep need and can cause excessive daytime sleepiness.
These include:
In fact, one study states that sleep apnea is the most common cause of habitual drowsy driving. It shares that those with the sleep disorder are six times more likely to have accidents. But after sleep apnea treatment, the risk can be lowered by five times.
Medical conditions can also make it harder to get enough sleep, or they may have drowsiness as a symptom.
These include:
Certain medications come with drowsiness as a side effect, including antidepressants and over-the-counter medications like pain meds or antihistamines (ironically antihistamines are used for allergies, and allergies themselves can make you tired).
Some sleep aids can leave you feeling drowsy the next morning, too, and melatonin supplements can cause daytime sleepiness if taken at the wrong time.
Alcohol can make you feel sleepy, even after a full night’s sleep. And if you’re driving home after a late night out, you’ll have the added risk of being awake for longer, too.
It’s even worse if you’re sleep deprived and have had a drink. A 2015 study shows that alcohol consumption on top of sleep loss worsens attention lapses during driving. And a simulated driving study found that people with sleep apnea had a higher likelihood of falling asleep while driving than healthy individuals, and this got even worse with alcohol.
It’s not just drinking when driving though. Alcohol can disrupt your sleep, leaving you feeling more tired the next day. So a glass of wine before bed could leave you feeling drowsy on the next morning’s school run.
We’ve covered how long before bed you should stop drinking alcohol here. Check RISE for an exact time based on your circadian rhythm.
You may be falling asleep while driving, but not feeling tired, because you’re driving during a natural dip in energy as part of your circadian rhythm, you have a medical condition or side effect from medication, or because you’re sleep deprived and don’t feel it.
We easily adapt to sleep deprivation and may not even realize how tired we are. You may not feel sleepy when you’re on the go or busy at work, but when the monotony of driving sets in, you start nodding off.
Your driving performance may also be impacted without you realizing it. One study found participants were largely unaware of the increasing declines in mental performance they got from not getting enough sleep.
For more insight, we asked one of our sleep advisors Dr. Jamie Zeitzer, who’s the co-director of the Center for Sleep and Circadian Sciences at Stanford University.
“If you’re not tired, but still find yourself falling asleep behind the wheel, it may be your circadian rhythm at play. Even when you’ve had enough sleep, you’ll still experience a natural dip in energy in the afternoon and in the run-up to your usual bedtime. If possible, avoid driving during these times.”
We’ve covered why you’re always sleepy no matter how much sleep you get here.
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Those at most risk of drowsy driving include:
If you do shift work, you may be especially at risk of drowsy driving as you may experience both being out of sync with your circadian rhythm and sleep deprivation. A 2023 review found a strong link between nurses who work long hours, night shifts, or rotating shifts and an increased risk of drowsy driving and car crashes.
Teens, who are usually night owls, face the same problem. A 2022 study found later school times were linked to a significant drop in the number of students who reported drowsy driving. A later school time would give teens a chance to get more sleep and be more in sync with their circadian rhythms.
To stop falling asleep while driving, lower your sleep debt and avoid driving during your natural dips in energy. These are the best long-term actions to stop drowsy driving.
Here’s more on how to make that happen:
We’ve covered how to get more energy here, including both short-term and long-term solutions.
If you’re sleepy while driving, the best thing to do is pull over and get some rest or let someone else drive. Combining caffeine and a short nap can also help wake you up.
Research shows that 200 milligrams of caffeine (about two cups of coffee) combined with a short nap of fewer than 15 minutes eliminated mid-afternoon sleepiness for one hour. When participants had both caffeine and a nap, it reduced driving incidents to nearly 10-fold of those who had neither.
Caffeine can help, but it’s not as effective. For those who just had caffeine but didn’t nap, incidents reduced by a third.
If you can nap, keep it short. Naps longer than 20 minutes are likely to trigger sleep inertia, or grogginess. Give yourself some buffer time between waking up and driving again to ensure grogginess doesn't affect your driving skills (even if you’ve only napped for less than 20 minutes — it’s better to be safe than sorry).
Caffeine consumption also has its caveat: Caffeine can stay in your system for more than 12 hours. Avoid drinking it too late in the day or else you risk keeping yourself up that night. This could increase your sleep debt and the likelihood of drowsy driving the next day.
If you intend to drive long distances, plan your itinerary for a stop every 100 miles or two hours for two hours. Keep caffeinated drinks in your vehicle in case you need an alertness boost. And stay away from alcohol or medications that induce drowsiness.
If you feel drowsy, pull over.
But you can try these things to help keep drowsiness at bay:
Many methods used to wake yourself up when driving don’t work. These include:
These actions can be useful to keep your energy levels high when you’re not drowsy. But if you do feel drowsy, pull over at a rest stop or let a passenger takeover.
The best way to stop falling asleep at the wheel is to get enough sleep before you step foot in the car and to avoid driving during your natural dips in energy. For more energy overall, sync up with your circadian rhythm and keep your sleep debt low.
The RISE app acts as a “breathalyzer” for drowsy driving. It works out how much sleep debt you have, so you can see whether you’re too sleep deprived to drive. RISE can also predict your circadian rhythm each day, so you can see when your energy levels will be higher and lower and when it’s best to avoid driving.
Use RISE to get more energy fast — 80% of RISE users report feeling more energy within five days.
You may be falling asleep while driving because you haven’t slept enough, you’re driving during a natural dip in energy (part of your circadian rhythm) that usually happens around 1 p.m. to 3 p.m., you have a medical condition or sleep disorder, take certain medications, or have had alcohol.
You may be sleeping while driving during the day because you haven’t slept enough, you’re driving during a natural dip in energy (part of your circadian rhythm) that usually happens around 1 p.m. to 3 p.m., you have a medical condition or sleep disorder, take certain medications, or have had alcohol.
If you’re falling asleep while driving but not tired, you may also be sleep deprived and not realize it as we grow used to the effects of sleep loss. You may also be driving during a natural dip in energy that comes as part of your circadian rhythm around 1 p.m. to 3 p.m., have a medical condition or side effects from medications, or have had alcohol.
To wake yourself up while driving, pull over, drink two cups of coffee, and take a short 15-minute nap. The safest thing to do is to let someone else drive. To prevent drowsy driving happening in the future, lower your sleep debt and avoid driving during your natural dips in energy (like during the afternoon or late at night).
To avoid falling asleep while driving, lower your sleep debt, avoid driving during your natural dips in energy (like during the afternoon or late at night), get checked for a medical condition or sleep disorder, and avoid drinking and driving.
A microsleep while driving is when you fall asleep for a few seconds behind the wheel. You may notice yourself nodding off or you may not even realize it’s happening. Either way, microsleeps while driving can be dangerous and life-threatening.
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