Driver fatigue or tiredness is a cause for one fifth of car accidents and is responsible for around 300 deaths per year in UK.
Driving when tired after having little or no sleep, is extremely dangerous, if you fall asleep behind the wheel and cause a car accident, you are 50% more likely to die or suffer serious injury because a sleeping driver does not react before a crash.
Furthermore, tiredness and sleepiness can affect any driver, despite the common misconception that it is dangerous only for the people who drive for a living.
It is advised not to plan any long travels by car between midnight-6am and 2-4pm, as these are periods of the day when the natural alertness is at its lowest. If it is not possible for you to avoid the travel, make sure you take 15 minute breaks every two hours and have some strong coffee before you sit behind the wheel. Keep in mind, though, that its effect will only last for a coupe of hours at most, so take breaks and have the rest you need.
In addition, be cautious if you are on special medication that can tire you out quickly or cause sleepiness. If possible, avoid driving or ask someone else to do it for you, so that the risk of a car accident is minimised.