Drivers on the Basingstoke by-pass used to have their attention diverted by a sign that reads A MOMENT'S INATTENTION CAUSES ACCIDENTS. This self-defeating warning has now been removed, but its message is still very much to the point. Almost anything can cause an accident. Apart from momentary inattention, it might be a minor miscalculation, a sudden fit of coughing, a bop on the head with a teddy-bear from a child in the back seat, an argument with the wife, fog, falling asleep at the wheel, bad eyesight, a glaring sun, ice, rain, wind, or snow-all these can make the difference between a tragic hit and a lucky miss. Although human error plays its part, it is by no means the only cause of accidents. There must be some cause other than simple human error. Road construction plays its part: researchers have found that it is not at the obvious danger spot- sharp corners, cross-roads, narrow lanes — that accidents happen. It is on those roads where there are subtle visual traps, unexpected changes in the shape or surface of the road, or even insufficient or badly-placed signs. Wherever there is a 'black spot', it means that something is seriously wrong with the road. Why else did the careless driving of so many come out at that particular spot? What the law requires when you have an accident. There are, firstly the legal formalities of exchanging names and addresses with others involved in an accident and, in Certain cases, informing the police. However, you are required by law to stop after an accident only if. 1. Somebody other than yourself in or outside your car has been injured. 2. A vehicle not of your own has been damaged. 3. Any horse, cow, donkey, sheep, or dog has been injured. It has been said that if a driver continues unaware of causing injury he must be acquitted. But the courts are wary of that excuse. Furthermore, the driver himself must wait at the scene; it is not enough for him to leave his chauffeur or a friend to attend to the boring formalities while he goes off on more important business. If you have been involved in an accident and have stopped, you must give your name, address, and registration number to anyone who has a good reason for requesting it; this means anyone affected by the accident. If these formalities which are complied with it is not necessary to wait for the arrival of the police. It is, however, often wise to do so. The police are experts at drawing plans, taking measurements and photographs and gathering other evidence. In your absence the police could be given a biased story against you; and you yourself might warn to point out certain features of the accident to the police. A MOMENT'S INATTENTION CAUSES ACCIDENTS (para. 1) is a self-defeating warning because ______ .