All species in nature need signals to facilitate interaction. The first driver signals were hand waving. In darkness, and at high speeds hand signals do not work. During the 1920s the first national and international regulations and standards on vehicle signal lights were developed. Over the years the requirements in terms of intensity, area and colour have gradually increased. More and more specialised signal lamps and markings have been introduced. At the front of the vehicle the direction indicators, the parking lights and the daytime running lights are the main signals lights. At the rear the situation is much more complex with position lamps, direction indicators, brake lamps, back up lamps, high mounted brake lamps, and fog lamps. But beside the lamps, the rear and the sides are also equipped with passive signals such as retro-reflective markings. The tasks and effectiveness of the signal lights are discussed. It is concluded, that current vehicle markings and signal lights - especially the rear lights - show a number of limitations. It is however, a sensitive task to change present signal lamps considering how well established they are. A first step towards improvement could be to make the signal lights more intelligent, e.g. adapting to the ambient level of illumination. A more radical approach to solve the dilemma could be fully intelligent and interactive signal systems as a component in a more complete ITS. (A)
Samenvatting