Fatigue

People often think that driver fatigue means falling asleep at the wheel. Falling asleep, however, is an extreme form of fatigue.

Fatigue is tiredness, weariness or exhaustion. You can be fatigued enough for it to impair your driving long before you ‘nod off’ at the wheel. For example, when you are fatigued:

• your reactions are much slower

• your ability to concentrate is reduced

• it takes longer to interpret and understand the traffic situation.

In 2018, fatigue was a contributing factor in 22 fatal crashes, 99 serious injury crashes and 556 minor injury crashes.*

Why is fatigue a problem?

The most common effects of fatigue on driving are:

• difficulty keeping your car within a lane

• drifting off the road

• more frequent and unnecessary changes in speed

• not reacting in time to avoid a dangerous situation.

These effects lead to a high number of single vehicle crashes involving a car striking a tree or other rigid object, and severe head-on collisions.

Driver fatigue is difficult to identify or recognise as contributing to a crash. This means it’s likely that fatigue is under-recorded, and contributes to more crashes than we realise. Australian estimates indicate that fatigue accounts for up to 30 percent of single-vehicle crashes in rural areas. Fatigue needs to be taken very seriously.

How does fatigue interact with other factors that affect driving?

Driver fatigue often combines with other factors, such as alcohol and speed, to cause road crashes.

Alcohol

Drink-driving is particularly dangerous in combination with fatigue. Alcohol can affect a driver’s alertness long before the legal limit is reached. Any amount of alcohol can combine with fatigue to affect your driving.

Speed

Speed and fatigue are also a bad combination. The faster you drive, the less time you have to react to the unexpected. When you’re tired, fatigue slows your reactions. It’s possible that speed makes up a larger proportion of fatigue-related crashes than we can identify. 

Who is affected?

While all drivers are likely to experience fatigue to some degree, fatigue is more likely for:

• young people

• shift workers

• people with sleep disorders.

Tips on avoiding fatigue

• Get a good night's sleep before driving, preferably eight hours.

• Avoid driving during the hours when you would normally be sleeping.

• If you normally have a mid-afternoon nap, then you should avoid driving at that time.

• Make sure you are fully awake before driving following a period of sleep.

• Share the driving when possible.

• Don't drink even small amounts of alcohol. It will make the effects of fatigue much worse.

• When taking long trips, plan your journey to include regular rest breaks, at least every 2 hours.

• Ensure you get plenty of fresh air.

• Snack on light, fresh foods. Avoid consuming fatty, sugary or carbohydrate-filled foods, which can make you feel tired.

• If possible, avoid driving for several days following long distance air travel. Jetlag can creep up on you and you may not even feel tired.

• Take a friend with you on your travel who will help you stay awake.

• If seriously tired take a 15-20 minute nap (no more than this). This is effective in restoring alertness and focus as a short term solution. 

• Avoid taking any medication that may lead to drowsiness.

How at risk are you?

Calculate your driver fatigue rating

Want to know more?

Read more tips on how to stay alert and avoid driver fatigue in The official New Zealand road code. 

Download Factsheet 24 – Fatigue: staying alert while you're driving [PDF, 60 KB]

Drive for a living?

See more information on work time and logbooks and identifying and preventing fatigue for commercial drivers.

* Note: Crash data for 2018 is not yet complete. Data is for all crashes reported by the Police to the NZ Transport Agency for the year 2018 as recorded in CAS at 19/06/2019.