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
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February 2, 2024
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Things you should know:

  • Drowsiness  can be caused by insufficient sleep or being awake during the night-time  hours  
  • Driving  after being awake for extended periods of time (e.g., 17 hours or more) can impair performance to a similar level as having a blood alcohol concentration  of 0.05%
  • People  under 25, who work shift work, or have a sleep disorder are at a higher risk
  • If you're drowsy, finding a safe place to stop and taking a 15- to 20-minute nap  can lower your risk of having a near miss or accident
  • 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 percent of Australians have driven while drowsy in the last month, and 20 percent reported having fallen asleep while driving. Crashes as a result of drowsy driving 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 can decrease to a level that is similar to having a blood alcohol concentration level of 0.05 percent. Getting up at 7am in the morning, staying awake during the day, going out in the evening and then driving home at midnight gets you to this level of continuous wakefulness which has the potential to impair performance.

Twenty-four hours without sleep can result in performance impairments similar to those associated with a blood alcohol concentration level of 0.10 percent, which is over the legal limit in Australia.

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 and Narcolepsy have a much higher risk of having a crash due to sleepiness.

What are the warning signs?

It’s important to know what some of the warning signs of drowsy driving are:

  • Feeling excessively 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. A buddy system is a great idea and works well to help share the driving. 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, safe spot, put the seat back and take a nap of about 15- to 20-minutes, no longer. After your nap get, out of the car and walk around for 5- to 10-minutes before driving again. 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 as effective.

Does caffeine help?

Caffeine can offer some short-term help with alertness and may help for an hour or two. Small, regular doses of caffeine may help maintain alertness. Sugar is usually 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?


Download a PDF of this Fact Sheet

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