Speed humps, speed bumps, and speed cushions are all traffic calming devices used to slow down vehicles in areas where speed needs to be controlled, like residential streets, parking lots, and school zones. However, they differ in design, purpose, and how they impact vehicles. Our office can will determine which option is appropriate based on road eligibility.
Speed Humps:
Speed humps are raised areas of pavement, usually about 3 to 4 inches high, but they are wider and more gradual than speed bumps. Their width is typically 10 to 14 feet (3 to 4.3 meters), meaning the vehicle crosses the hump over a longer distance. They are designed to reduce vehicle speed to about 10 to 20 mph (15 to 30 km/h) without causing a harsh jolt. Because they are more gradual, speed humps create a smoother transition for vehicles, making them less disruptive for both drivers and passengers compared to speed bumps.
Use: Speed humps are commonly found in residential areas and roads with relatively light traffic, where moderate speed reduction is needed.
Speed Bumps:
Speed bumps are much shorter in length than speed humps, typically only about 1 to 3 feet wide (30 to 90 cm), and they are about the same height as humps (3 to 4 inches). They are designed to force drivers to slow down to a very low speed, around 5 to 10 mph (8 to 16 km/h). Speed bumps create a more abrupt change in elevation, which forces drivers to slow down significantly. If a vehicle goes over a speed bump too fast, it can cause discomfort and even damage to the vehicle.
Use: Speed bumps are commonly used in parking lots, driveways, and areas where very low speeds are required.
Speed Cushions:
Speed cushions are similar in function to speed humps but differ in design. They are a series of raised areas, typically wider than a single wheel track but narrower than the entire vehicle width. This means that larger vehicles, such as emergency vehicles or buses, can straddle the cushions without slowing down significantly. They are designed to reduce the speed of smaller vehicles, such as cars, while allowing larger vehicles to pass with minimal disruption. Speed cushions cause cars to slow down while allowing emergency or service vehicles to maintain their speed since the wider wheelbase can bypass the raised portions.
Use: Speed cushions are commonly used in areas where it's important to maintain accessibility for emergency services, such as bus routes or emergency vehicle corridors, while still controlling the speed of regular traffic.
In short:
- Speed Humps: Gradual and wider, designed to slow vehicles to moderate speeds (10-20 mph).
- Speed Bumps: Short and abrupt, designed to slow vehicles to very low speeds (5-10 mph).
- Speed Cushions: Allow larger vehicles to pass with less disruption while still slowing smaller vehicles.
