Drivers tend to be over-confident about the safety of driving at high speeds, and there are several reasons why they underestimate the importance of speed from a safety viewpoint. Researchers see a clear relation between speed level on a specific road and the risk level and number of crashes on that road. G Nilsson et al. have found that a speed reduction from 55kph to 50kph, or from 110kph to 100kph, reduces the risk of being killed by 30%, of being severely injured by 25%, and of being injured by 20%. In built-up areas, with many pedestrians and cyclists, absolute speed of vehicles is more important than speed differences. Speeds are increasing, because speed is less noticeable in modern cars; speedometers are inaccurate and should instead show kinetic energy. Research has shown that twelve factors influence speed levels; most of them are driver perceptions and attitudes that increase speed; only one of them reduces speed. Large international differences of opinion on speed are gradually reducing, and eventually the European Union will have a common speed limit. Speeds should be reduced until really safe roads and cars can be built. All methods of reducing speeds have their advantages and disadvantages; they include speed limits, information, education, legislation, enforcement, physical methods, and telematics.
Samenvatting