Speed bumps (or speed breakers) are the common name for a family 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 found to enforce a low speed limit, under 40 km/h (25 mph) or lower.
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. Many sports cars have this problem with such speed bumps. Speed bumps can also pose serious hazards to motorcyclistsand bicyclists if they are not clearly visible, though in some cases a small cut across the bump allows those vehicles to traverse without impediment. Speed bumps cost $50–200 and may need replacement over time due to wear.