This occurs when people are tired but are trying to stay awake, most common in monotonous situations. Nodding off for just a few seconds at the wheel can be fatal: if you are driving on a motorway at 70mph and nod off for six seconds you would travel nearly 200 metres, which could take you across three lanes of traffic and down an embankment onto another road or train track.

Look out for the Warning Signs

Research shows that normal sleep does not occur without warning. You should know when you are starting to feel sleepy. Warning signs include: increased difficulty concentrating; yawning; heavy eyelids; eyes starting to 'roll'; and neck muscles relaxing, making the head droop. If you experience these symptoms, you should find somewhere safe to rest as soon as possible, rather than trying to fight off tiredness. Winding down the window, listening to music and talking to a passenger do not help prevent sleep, although they may temporarily help you to stay alert until you find somewhere safe to stop.

Laws
If you are found to be driving tired, you may be charged with:
• careless driving (when driving has fallen below the standard expected of a careful and competent driver);
• dangerous driving (when driving has fallen far below the standard expected of a careful and competent driver).

If you cause a death while driving tired, you can be charged with death by dangerous driving, if there is sufficient evidence available. The maximum penalty for death by dangerous driving is 14 years in prison.

If you need to drive here is some safety advice

If you start to feel sleepy while driving:
• Stop for a 15 minute break somewhere safe as soon as possible. This should never be on the hard shoulder as this is extremely dangerous.
• If you drink caffeine, drink two cups of coffee or a high-caffeine drink, such as an energy drink.
• Take a 10-15 minute rest or snooze, but no longer as you will go into a different type of sleep. Set an alarm clock to wake you. By the time you wake up the caffeine will have kicked in and you should be ready to continue your journey.

If you still feel tired, you should not continue your journey.
• Bear in mind that the caffeine is a temporary drug and its effects do not last long. Sleep is the only long-term cure to tiredness.