Drivers on the Basingstoke by-pass used to have their attention diverted by a sign that read-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. Although human error plays its part, it is by no means the only cause of accidents. There must be some causes other than simple human error. Road construction also plays its part. It is on those roads where there arc subtle visual traps. Wherever there is a 'black spot', it means that something is seriously wrong with the road. If you have been involved in an accident and have been 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 accidents. If somebody is injured, the driver must produce his insurance certificate on request. If these formalities 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 expert 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 want to point out certain features of the accident to the police. A MOMENT'S INATTENTION CAUSES ACCIDENTS is a self-defeating warning because______.