Speed bumps seem to have been adorning British roads forever. Not a week goes by without someone venting their frustration about these traffic calming devices in the press or on television. Just, what do they offer in terms of safety and what are the risks involved in adopting them?
Where it all started
Speed bumps were first introduced in Europe in 1970 and the UK has been using them as traffic speed control measures for some time (the first mention of them appears in the 1980s). They take many forms, are made of many substances and have many names (speed ramps, sleeping policemen and kipping cops to name a few). The latest generation of dynamic speed bumps only operate if you are travelling above a given speed. Speed humps are often considered different in that they have a less aggressive design.
Clearly, the major positive of these traffic calming measures is evident from their name. Their sole raison d'etre is to slow road traffic in sensitive areas. This is why we see them installed in the vicinity of schools, in residential areas and, increasingly, near retirement homes. The theory is that these lower vehicle speeds will give both drivers and pedestrians more time to react to one another and thus, reduce the incidence of injury to vulnerable members of the community. A 1993 Dutch study in 151 30 kmh zones showed a reduction rate of 22% in accidents involving personal injury. An ongoing study in six German cities showed that, though the number of accidents increased slightly, the number of casualties decreased. Research in London corroborates this with an injury reduction of 31%.
The major objection that most people have towards speed bumps is that they increase the response time for emergency vehicles. New designs of bumps are nullifying this impact however, and it is expected that this will cease to be an issue over the next few years. Allied to this, have been claims by the emergency services that their vehicles require more frequent damage repairs in areas where bumps are installed. Car drivers often complain of both personal discomfort and increased mechanical stress to their vehicles, although it can be argued that neither of these will occur if the correct speed is maintained. Complaints by nearby residents of increased pollution due to uneconomical engine operation at low speeds are justified and proven. However, given the fact that traffic levels tend to drop in speed-controlled areas, it may be the fact that this is balanced-out. Finally, it is possible that drivers are distracted by speed bumps and end up less aware of their environment. They also have a tendency to speed-up between control measures.