A speed bump (in British English a speed or road hump, sometimes colloquially a sleeping policeman) is a traffic calming tool designed to slow traffic or reduce through traffic. A speed bump is a bump in a roadway with heights typically ranging between 3 to 4 inches (7 to 10 cm). The length of speed bumps are typically less than or near to 1 foot (30 cm); whereas speed humps are longer and are typically 10 to 14 feet (3 to 4 m) in length.
The use of speed bumps is widespread around the world, and they are most commonly found where prevailing vehicle speeds are expected to be low. Although speed bumps are very effective in keeping vehicle speed down, their use is sometimes controversial as they can cause noise and possibly vehicle damage if taken at too great a speed. Poorly designed speed bumps often found in private car parks (too tall, too sharp an angle for the expected speed) can be hard to negotiate in vehicles with low ground clearance, such as sports cars, even at very slow speeds. Speed bumps can also pose serious hazards to motorcyclists and bicyclists should they fall to the ground.