Pedestrian Safety Guide and Countermeasure Selection System
A speed table. Source: Federal Highway Administration
Speed humps are paved (usually asphalt) and approximately 3 to 4 in. high at their center, and extend the full width of the street with height tapering near the drain gutter to allow unimpeded bicycle travel. Speed humps should not be confused with the speed “bump” that is often found in mall parking lots. There are several designs for speed humps. The traditional 12 ft hump has a design speed of 15 to 20 mi/h, 14 ft hump a few mph higher, and a 22 ft table has a design speed of 25 to 30 mi/h. The longer humps are much gentler for larger vehicles.
In general, speed humps are a device of last resort. Other traffic calming solutions should be considered first. However, they may be the best solution is some situations, especially on long, straight residential streets where there are few intersections and no other visual cues to slow motorists.
A “speed table” is a term used to describe a very long and broad speed hump, or a flat-topped speed hump, where sometimes a pedestrian crossing is provided in the flat portion of the speed table. The speed table can either be parabolic, making it more like a speed hump, or trapezoidal. Speed tables can be used in combination with curb extensions where parking exists.9