What is the British slang nickname for a road speed bump?

The British slang nickname for a road speed bump is “sleeping policeman.”

A speed bump is a traffic-calming device that creates vertical deflection in the road, encouraging drivers to slow down. In British English, “sleeping policeman” is a familiar informal name for this raised obstruction. The image is straightforward: a policeman is imagined as lying across the road, quietly forcing traffic to pay attention.

The term is not universal English. New Zealand commonly uses “judder bar,” while “speed hump,” “speed cushion,” and “speed table” describe related designs rather than always serving as exact synonyms. A speed table has a broad, flat top; a speed cushion has separate raised sections that can sometimes allow wider emergency vehicles to pass more easily.

Speed bumps can improve safety and reduce vehicle speeds, especially in residential streets, car parks, and areas near pedestrians. They also have trade-offs: vehicles driven over them too quickly can be damaged, traffic noise may increase, and emergency journeys can take longer. The nickname should therefore be distinguished from the technical descriptions used by transport engineers.