Drowsy Driving

This is a fact sheet about Drowsy Driving. Drowsy driving is the act of operating a vehicle while excessively sleepy, which can impair a driver's ability to stay alert & make split-second decisions.

Driver's view inside a car. Photo by Lukas Rychvalsky
September 24, 2023


Things you should know:

  • Drowsiness can be caused by insufficient sleep or being awake during the nighttime hours.
  • Driving while you are drowsy can make your driving worse than if you have been drinking alcohol.
  • People under 25, who work shift work, or have a sleep disorder are most at risk.
  • If drowsy, find a safe place to stop for a 15- to 20-minute nap to lower your risk of a crash.
  • Learn to recognise the warning signs of drowsiness and take action.

Have you ever driven while drowsy?

Many people drive while they are drowsy. A 2016 survey found that 29% of Australians have driven drowsy in the last month, and 20% reported having fallen asleep while driving. These crashes are more likely to result in death or serious injury of the driver and other road users. Planning your journey and taking effective action when feeling drowsy is an important part of reducing the risk of drowsiness.  

How bad can it make your driving?

If you drive after 17 hours without sleep, your performance is as bad as driving with a blood alcohol level of 0.05 percent. Getting up at 7 in the morning, staying awake during the day, going out in the evening and then driving home at midnight gets you to this level.

Twenty-four hours without sleep is as dangerous as driving with a blood alcohol level of 0.10 percent.

You need at least 6 hours of sleep in the last 24 hours prior to driving.

Who is most at risk?

Statistics show that drivers 25 years or younger are more likely to be involved in a drowsiness related crash. Shift workers are also at high risk, as are long distance truck drivers. People with sleep disorders such as Obstructive Sleep Apnoea (OSA) and Narcolepsy have a much higher risk of having a crash due to sleepiness.

What are the warning signs?

Warning signs may be present to indicate a high risk of a crash. These are:

  • Feeling sleepy.
  • Struggling to keep the eyes open or going out of focus, very heavy eyelids.
  • Wandering thoughts, difficulty concentrating on driving, and missing signs.
  • Cannot remember driving the past few kilometres.
  • Drifting between lanes, swerving off the road or struggling to maintain speed.
  • Doing things to keep yourself alert, such as winding down the window or turning up air conditioning or music.
  • Head nodding - this is end-stage drowsiness, indicating that you are already having micro-sleeps.

What strategies can help prevent drowsy driving?

If you need to drive a long distance, make sure you have had plenty of sleep the night before. Driving at night or in the sleepy period straight after lunch can be particularly risky. Most crashes happen when you have had less than 6 hours sleep. If you must drive for extended periods of time, try to take a short power nap after lunch. A buddy system is a great idea and works well - share the driving and share keeping each other awake. Have a break every 2 hours, get out of the car and walk around for a few minutes. Don't rely on loud music, open windows or passengers to keep you awake. The best cure for drowsiness is sleep. If the warning signs are there, you should stop driving and take a break. If you have regular drowsiness while driving, see your doctor to identify the cause.

How long should a "power nap" be?

A short nap may refresh you enough to continue driving for another couple of hours. Pull over to a quiet spot, put the seatback and take a nap of about 15- to 20-minutes, no longer. After your nap get out of the car, walk around for 5 minutes and then drive on. Be aware of the signs of drowsiness and avoid the temptation to go just that little bit further. Naps at night or if you have not had adequate prior sleep may not be effective.

Does caffeine help?

Caffeine does offer some short-term help with alertness and may help for an hour or two. Small, regular doses of caffeine may maintain alertness better than a single large dose. Sugar is not helpful and can make you sleepier after 30-90 minutes compared to if you had no sugar.

How many crashes are caused by drowsy drivers?

Statistics show that around 20 to 30 percent of fatal crashes result from drowsy driving. Up to one in four crashes on country roads that involve only one car are due to the driver falling asleep. In Australia, the cost to the community of drowsy driving crashes could be up to $3 billion every year.

Where can I find out more information?

Drowsy Driving: Dangers and How To Avoid It | Sleep Foundation 

Other useful links: