Driver fatigue is a recognised problem responsible for a high proportion of road traffic accidents. Researchers at Loughborough University in the UK used driving simulators and tired 
volunteers to test various methods of overcoming driver tiredness. The test included opening windows to blast cold air at the driver, slapping themselves in the face and playing loud music. None of these remedies worked as well as a cup of coffee and a short nap. Researchers found coffee helps clear your system of adenosine, a chemical which makes you sleepy.
You might like to try this yourself when feeling sleepy during the daytime. Have a cup of coffee and then immediately go to sleep for exactly 15 minutes. You need to set your watch or maybe your appointment calendar if you are at your PC to wake you after 15 minutes. The caffeine nap was the most effective way to overcome tiredness fast.
Of course the success of this depends on your ability to fall asleep immediatly, before the caffeine works its way into your system and stops you sleeping.
