Stay awake, stay alive. Every year, thousands of motorway accidents seem to be caused by drivers falling asleep : the problem is particulary acute at early morning and late afternoon.

This article describes recent British work which supports the claim made by British Police Forces and also by Sleep Laboratories throughout the world that from 13% to 20% of accidents could be caused by drivers falling asleep at the wheel. Brief details of this evidence are provided. The British pilot study, undertaken jointly by the Sleep Research Laboratory at Loughborough University and Leicestershire Police was undertaken in August 1991 among people driving on Midland motorways. Police officers interviewed 58 drivers who had either been involved in sleep related accidents, such as running off the motorway, or sleep related incidents, such as drifting across the motorway lanes. Drivers who were asleep while parked on the hard shoulder were also interviewed. The questions asked included the number of hours since the driver last slept, the length and quality of that sleep, the time since the journey began, time since last break from driving, the distance driven and whether the driver was on shift work. It was found that of the 58 cases or incidents, many were clustered in three periods of the day: midnight to 2 am, 4 am to 6 am, and 2 pm to 4 pm, with the 4 am to 6 am period being the most dangerous. About 11% of all motorway accidents occur between 4 am and 6 am, even though traffic density at these times is 20% of the daily average. These findings support those from the United States and other countries. Concern is also expressed over the poorly substantiated phenomenon known as "highway hypnosis" or "driving without awareness" (DWA), and the fact that many lorry drivers are also said to regularly fall asleep at the wheel although the latter claim is unsubstantiated.