Speed bump

Speed bumps are a class of traffic calming devices that use vertical deflection to slow motor-vehicle traffic in order to improve safety conditions. Speed bumps are also known as a sleeping policeman in British English, Maltese English and Caribbean English, a judder bar in New Zealand English, and a lying-down policeman in Colombia, Dominican Republic, Hungary, Croatia, Serbia, Estonia, Lithuania, Slovenia, Bulgaria and Russia. 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).

Although speed bumps are effective in keeping vehicle speeds down, their use is sometimes controversial—as they can increase traffic noise, may damage vehicles if traversed at too great a speed, and slow emergency vehicles. Poorly-designed speed bumps that stand too tall or with too-sharp an angle can be disruptive for drivers, and may be difficult to navigate for vehicles with low ground clearance, even at very low speeds. The several variations of traditional speed bumps exist to mitigate some of these issues.