minimum amount of required sleep before long drive
Questions And Answers

How Much Sleep Do You Need to Drive a Car Safely?

(Last Updated On: August 14, 2022)

According to the Foundation for Traffic Safety (FTT), 45% of Americans admitted to driving when tired. Given that drowsiness and drunkenness affect the brain in similar ways, this is a worrying statistic.

Long commutes, irregular shift patterns, and busy social lives may be responsible. Many of us feel under pressure to get from A to B as quickly as possible – no matter how tired we feel.

Sleep Requirements for Safe Driving

According to the U.S. Department of Transportation, the only way to ensure safe driving is to get 7-8 hours of quality sleep each night. However, if you want to drive safely, you’ll need to be aware of the following:

  • The signs of drowsiness can be difficult to recognize, so you’ll need to stay vigilant.
  • Certain groups (truck drivers, teenagers, people with sleep disorders, etc.) are more susceptible to falling asleep at the wheel.
  • Tiredness is sometimes unavoidable. If you’re nodding off at the wheel and there’s nowhere safe to stop, there are ways to temporarily perk yourself up until you’re able to rest.
  • The drowsy-driving laws vary from state to state. Also, non-government campaigners play an active role in reducing drowsy-driving crashes, so note their recommendations.

Why Is Sleep Important for Driving?

Here’s how sleep can help us become safer drivers:

  • Reaction times – Studies have shown that sleep-deprived individuals take longer to make decisions. In addition, people who’ve had less sleep make poorer judgments when rushed. Imagine how many split-second judgments you make during a one-hour drive.
  • Concentration – Our attention span lengthens when we’re well-rested. If you’re driving for a couple of hours, you’ll need to concentrate on road signs, traffic signals, and other drivers.
  • Mood – If you’ve had 8 hours of sleep, you’re less likely to lose your temper with fellow road users or back seat drivers. Outward displays of road rage can lead to crashes and collisions because you’re more likely to take dangerous risks when you’re feeling angry.
  • Spatial memory – This is important for learning road routes. Sleeping for 6-8 hours (undisturbed) helps to improve our spatial memory.
  • Procedural memory – This is your memory for ‘tasks.’ If you’re learning to drive or getting used to driving in a new vehicle, sleep will help you learn quicker. Procedural memories are rehearsed during the REM stages of sleep, and the highest quality REM stages occur after 6 hours of sleep.

Is Drowsy Driving a Big Problem?

According to the NHSTA, 100,000 crashes reported to the U.S. police involved a drowsy driver. 3,000 died, and 76,000 were injured in drowsy driving-related motor crashes.

Unfortunately, many motorists are unaware of the risks of drowsy driving because crashes are sometimes misreported as drowsiness can be hard to prove.

Thankfully, there are many things you can do to stop yourself from falling asleep at the wheel. Let’s start by learning how to recognize the signs of fatigue.

Signs of Falling Asleep At The Wheel

Drowsiness can be hard to recognize, as we can’t predict sleep when we’re tired at the wheel. Fatigue can creep up on us, and we may not realize it until it’s too late.

If you experience any of the following symptoms when driving, you must act immediately:

  • Frequent yawning
  • Heavy and itchy eyes
  • Blurred vision and an inability to read road signs
  • Irritability and short temper
  • Inability to drive in a straight line
  • Head and neck starting to droop (head nodding)
  • Microsleeps, which involve dozing off for 2-3 seconds

Symptoms like these should never be ignored.

driving fatigue symptoms

Why Are Microsleeps So Dangerous?

During microsleeps, our brainwaves change from an alpha state to a theta state. In other words, brain activity slows down considerably. During a microsleep, we become unaware of our surroundings.

Imagine traveling along a highway at 70 mph, and you fall asleep for 5 seconds. This means you’d travel 157.5 meters blind. Added to this, microsleeps can last for up to 30 seconds.

Perhaps the most dangerous thing about microsleeps is our inability to recognize them. Most of the time, you won’t even be aware you’ve had a microsleep. This is worrying because it stops you from intervening and taking some much-needed rest.

Even if microsleeps don’t immediately lead to a collision, consecutive microsleeps will impair your judgments. Studies have shown that having several microsleeps lead to confusion and distress.

Tasks like giving way, changing lanes, or slowing your speed can become difficult following microsleeps.

How To Be More Alert While Driving

If you’re feeling weary at the wheel, the ideal thing to do is stop your car and sleep for 8 hours. However, if you’re on a busy highway, stopping your vehicle may not be safe.

If you find yourself in this situation, consider the following short short-term solutions:

  • Open the car windows and allow some fresh air to circulate.
  • Turn the radio on and play some upbeat music.
  • Ask a passenger to talk to you.


According to the NHTSA, you should look for a designated rest place and take a nap as soon as you feel tired. Naps should last 45 minutes, but a 10-20-minute nap will be beneficial.

Studies have shown that napping can increase alertness for 2-3 hours.

When you wake up from your nap, wait 5-10 minutes before driving off. This will ensure you are fully awake and ready to face the rest of your journey.

Caffeinated Drinks

Coffee is another short-term solution that can help you feel more awake. According to the Transportation Research Board, caffeine helped sleep-deprived drivers maintain the correct speed and stay in the right lane during a driving simulation.

In this study, the drivers were given 4 x 200 mg of coffee over 24 hours (200 mg is equivalent to one strong cup of coffee).

The NHTSA recommends drivers pull over and drink 1-2 cups of coffee (or a caffeinated beverage) as soon as they feel sleepy. Drivers should rest for 15 minutes before driving off to allow the effects of caffeine to take hold.

Caffeine is a short-term solution. You should limit your intake to four cups of strong coffee per 24 hours because too much coffee can make it difficult to recognize microsleeps.

How To Prevent Drowsy Driving

Did you know that sleeping for only four hours increases your risk of having a crash by 11.5 times?

If you work long night shifts at work or you’re used to grabbing sleep whenever you can, you’re probably skeptical about the possibility of sleeping for 8 hours a night.

Try some of these tips to see if they make a difference:

Good Sleep Hygiene

Try to go to bed at the same time each night to establish a healthy sleep routine. Remember, you should aim for 7-8 hours of sleep per night, so set your bedtime accordingly.

Make your bedroom as dark as possible to encourage melatonin production, and keep electronics out of the bedroom to avoid over-stimulating the brain.

Sleep Comfort

When it comes to getting a good night’s sleep, don’t underestimate the importance of comfort. Choose a quality mattress and pillows to relax.

Healthy Diet

A study by the FMCSA found that CMV drivers who had crashed due to drowsiness often had poor diets. Indeed, sleep deprivation can lead to overeating because it interferes with appetite regulation.

Try to eat regular, balanced meals to avoid fluctuating hunger levels. Also, avoid eating heavy meals before bedtime as this can disturb sleep.

Working Hours

Many of us take on regular overtime to help pay the bills. It’s not only truck and taxi drivers that can suffer drowsiness at the wheel; it’s an overworked person who drives as part of their commute.

Try to manage your workload and ensure you’re following your employer’s policy for fatigue prevention.


Keep a bottle of water and drink regularly to stay hydrated, as you’ll find it easier to focus on the road.

Drowsy Meds

The FMCSA found that 17% of drivers involved in crashes had taken over-the-counter drowsy medications in the 12 hours before the crash.

It’s common for OTC cold, flu, and hay fever medicines to make you feel drowsy.

You should avoid driving when you have the flu, as influenza can slow down your reflexes. If you have a light cold or hay fever, choose non-drowsy medications if you know you’ll be driving.

Share the Driving

If you’re going on a long road trip, share the driving with a friend or family member.

Plan Your Route

Plan your route so you can schedule some rest breaks into your journey. This will take the stress out of your journey, so you’re free to concentrate on driving.

When to Take Extra Care While Driving

Certain factors can make drowsy-driving crashes more likely, including:

Driving on the Freeway

Crashes caused by tired drivers are more likely to occur on the freeway because the driver lacks stimulation, so they may become overly relaxed.

If your journey incorporates long and boring roads, play some of your favorite music or listen to an interesting radio program to keep your mind focused.

Naturally Occurring Lulls

Our sleep/wake cycle operates based on a 24-hour clock known as circadian rhythm. At certain points in this cycle, our energy levels plummet.

Our energy levels are known to dip at the following times:

  • 12 am – 6 am
  • 2 pm – 4 pm

Studies have shown that crashes caused by drowsy drivers are more likely to happen during these hours. If you’re driving a long distance, schedule your rest breaks during these hours.

If you must drive at these times, consider drinking a cup of coffee and be extra vigilant regarding symptoms of drowsiness.

Sleep Inertia

Crashes are more likely to occur during the first hour of driving, which could be because the driver hasn’t allowed themselves sufficient time to wake up from sleep.

Truck drivers who sleep in their berths are most at risk of this phenomenon, as they’re more job-focused and less likely to allow themselves time to wake up slowly.

Truck Drivers And Drowsy Driving

According to the Department of Health and Human Services, truck drivers should aim for 8-9 hours’ sleep (rather than the standard 6-8 hours’ sleep).

If you’re a long-distance driver, consider the following tips:

  • Tell friends and family – If friends and family know how crucial your sleep is, they’re less likely to disturb you. Studies have shown that we’re more likely to make positive behavioral changes if we have the support of our family.
  • Stress relief – Being a driver can be stressful and isolating. During your time off, find ways to relieve stress but avoid stimulants like nicotine and energy drinks.
  • Prevention naps – According to the FMCSA, napping is more effective before you feel tired. If you regularly drive long distances, schedule naps into your journey.
  • Sleeping on the road – Try to pick a safe spot to park in but still fairly quiet. Ensure the temperature of your berth is conducive to sleep and consider buying a good-quality pillow to feel more comfortable. Also, put a blue filter on your phone if you keep it close to your bed.

Teenagers And Drowsy Driving

Teenagers’ brains are still developing, so their sleep requirements are greater than adults. Teenagers should regularly sleep for 7-9.5 hours per night.

At the same time, teenagers often stay up late and pull all-nighters, which makes them particularly susceptible to becoming tired at the wheel.

Teenagers are inexperienced drivers. Sleep will enable them to become better drivers because good quality REM sleep strengthens procedural and spatial memory skills.

If they miss their sleep, they’re more likely to be hesitant drivers.

Sleep Disorders And Drowsy Driving

The American Sleep Association estimates that up to 70 million Americans suffer from chronic sleep disorders. The most prevalent sleep disorders that directly affect a person’s ability to drive are sleep apnea, narcolepsy, and insomnia.

Regulations regarding driving with narcolepsy vary from state to state. In most states, a doctor will be required to contact the DMV if you have a condition that may cause a loss of consciousness.

The FMCSA stated that a person might not be qualified to hold a commercial driving license if they have a condition that can affect their ability to operate safely (i.e., untreated or severe sleep apnea).

Procedures vary between states, although a diagnosis of sleep apnea would rarely stop someone from driving domestically.

Drowsy Driving vs. Drunk Driving

Feeling very sleepy can be as dangerous as feeling drunk. The cognitive effects of being drunk (poor coordination, slower judgments) are similar to those of being tired.

According to NCBI, after 17 hours of no sleep, cognitive performance is comparable to having a blood alcohol volume (BAC) of 0.05.

After 24 hours of no sleep, your brain responses indicate a BAC of 0.10. Most U.S. states set their BAC levels at 0.08, so you’re essentially over the legal limit if you drive after being awake for 24 hours.

After 36-48 hours of no sleep, you’ll likely experience hallucinations, severe memory loss, and regular microsleeps. It would be risky to drive in these conditions.

is it illegal to drive while sleep-deprived?

Is It Illegal to Drive While Tired?

The law regarding fatigued driving varies from state to state; Arkansas and New Jersey are the only states to legislate against drowsy driving.

Maggie’s Law – New Jersey

Named after Maggie McDonnell, a sleep-deprived driver killed in a 1997 crash, New Jersey’s ‘Maggie’s Law’ (National Driving Act of 2003) was the first U.S. law to specifically target drivers who haven’t slept for 24 or more hours.

Under Maggie’s Law, drivers found to have caused death due to sleep-deprived driving may be prosecuted for vehicular homicide carrying a maximum sentence of 10 years imprisonment and up to a $100,000 fine.

However, the law has been difficult to enforce, with only two convictions since its enactment in 2003.

Negligent Homicide – Arkansas

In 2013, Arkansas made drowsy driving an offense under its existing negligent homicide laws. The change in law classed fatigued driving as a Class B felony.

If a driver is convicted of causing death due to driving while fatigued, they could be imprisoned for up to 20 years and be fined up to $15,000.

Three people have been convicted since this law came into effect.

What Is Being Done to Reduce Accidents?

Although laws have been difficult to implement, charities, employers, and local governments are working to reduce the number of drowsy-driving road accidents.

Rumble Strips

Crashes caused by sleep deprivation are often roll-off-the-road crashes. An effective countermeasure to this type of crash is the installation of rumble strips along the edges of roads.

These rumble strips are patterns in the tarmac that, when driven over, cause vibrations, alerting the driver that they’re leaving the edge of the highway.

In certain locations in New York, rumble strips reduced roll-off-the-road incidences by 84%.

Drowsy Driving Awareness

Each November, the National Sleep Foundation holds a Drowsy Driving Prevention Week to raise awareness of the dangers of driving with insufficient rest.

The foundation releases facts and figures related to drowsy driving and educates people on the risks of driving without sufficient sleep. Also, some states have awareness initiatives.

Alabama and California have drowsy driver awareness days (November 19th and April 6th, respectively), and Florida and Texas promote drowsy driver awareness weeks in September and November.

Employer Responsibility

To reduce sleep-related accidents, employers must play their part.

Driving-related industries such as trucking companies, couriers, and taxi firms are responsible for abiding by national legislation regarding working hours.

In February, Uber introduced new policies, stipulating that drivers must take a minimum of 6 hours of rest following 12 hours of work.

However, individual employers have limited control over people who work multiple jobs, so employees must share some of the responsibility, too.

For the most part, tiredness is a personal complaint. However, when you get behind the wheel of a car, your tiredness could affect other road users. For this reason, you need to take drowsiness as seriously as other cognitive impairments, such as driving under the influence.

Concentration, judgment skills, and reflexes are significantly impaired when you’re tired.

To be a safe driver, you’ll need to regularly get 6-8 hours of sleep. If you drive as part of your job or are a teenage driver, get 8-9 hours of sleep.

Remember, if you need to fight fatigue at a moment’s notice, use caffeine, naps, and music (appropriately) to temporarily perk you up.