Speed bumps (also called traffic thresholds, speed breakers or sleeping policemen) are a class of traffic calming devices that use vertical deflection to slow motor-vehicle traffic in order to improve safety conditions. Variations include the speed hump, speed cushion, and speed table.
The use of vertical deflection devices is widespread around the world, and they are most commonly used to enforce a speed limit under 40 km/h (25 mph).
Traffic calming uses physical design, signs, painted markings, road use rule changes, and other transportation engineering measures to improve safety for motorists, car drivers, pedestrians, and cyclists. It has become a tool used by urban planners and road designers to combat speeding and other unsafe behaviours of drivers. It aims to encourage safer, more responsible driving and potentially reduce traffic flow. Urban planners and traffic engineers have many strategies for traffic calming, including narrowed roads and speed humps. Such measures are common in Australia and Europe (especially Northern Europe), but less so in North America, where the focus is often more on facilitating motorized traffic flow. Traffic calming is a calque (literal translation) of the German word Verkehrsberuhigung – the term's first published use in English was in 1985 by Carmen Hass-Klau.
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