Staying alert while you're driving

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.

Why fatigue is a problem

The most common effects of fatigue on driving are:

• difficulty keeping your car within the road
• drifting off the road
• 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. Fatigue needs to be taken very seriously.

How fatigue interacts 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.

Causes of fatigue

Sleep loss

Loss of sleep is one of the main, and most commonly known, causes of fatigue. Everyone has a basic sleep need. This can vary from person to person, but the average is seven to eight hours a day. If you don't get a full night's sleep, you're likely to be fatigued the following day. As little as two hours sleep loss on one occasion can affect reaction time, mental functioning, memory, mood and alertness.

People who are most likely to be affected by fatigue

While all drivers are likely to experience fatigue to some degree, fatigue is more likely for people in the following groups - ultimately leading to a higher crash risk:

• Young people – many young people have lifestyles that involve frequent late night activities, not getting enough sleep, taking risks and being on the roads during night-time hours.

Food and drink

Eat sensibly throughout the journey, but avoid large meals. They can make you drowsy, particularly at lunchtime.

Stay hydrated. Caffeine drinks (tea, coffee and cola drinks) help you stay alert, but they take time to be effective. Research has shown that drinking a caffeinated drink, followed by a 20 minute nap, improves alertness in the short term.

Get fresh air into the vehicle

You'll find it easier to stay alert if you have fresh air blowing into your vehicle. On long journeys it's best if you don't use the recirculating air function.

Environmental stimulation

Conversation and music can help you stay alert, but they're only short-term solutions. The best solution is finding somewhere to stop and sleep.