Speed humps are parabolic vertical traffic calming devices intended to slow traffic speeds on low volume, low speed roads. Speed humps are 3–4 inches high and 12–14 feet wide, with a ramp length of 3–6 feet, depending on target speed.
Speed humps reduce speeds to 15–20 mph and are often referred to as “bumps” on signage and by the general public.
Many residential streets have ample right-of-way for two lanes of travel plus parking, resulting in higher than desired speeds.
Adapted from the Urban Street Design Guide, published by Island Press.