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Speed
Hump & Speed Table | Raised
Intersection & Raised Pedestrian Crossing
Raised
Devices
Speed Hump & Speed Table
Speed humps are paved (usually asphalt) and approximately 3-4 inches
high at their center, and extend the full width of the street. Speed
humps should not be confused with a speed “bump” that is often found
in mall parking lots. There are several designs for speed humps.
The traditional 12-foot hump has a design speed of 15 to 20 mph,
a 14-foot one a few mph higher, and a 22-foot table, of 25 to 30
mph. The longer humps are much gentler for larger vehicles.
A speed table is a term used to describe a very long and broad speed
hump, or for 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, which is used more frequently in Europe. Speed
tables can be used in combination with curb extensions where parking
exists.
Speed humps are frequently used on residential
streets to reduce speeds. However, they can create unwanted noise
if they are too severe, or cause motorists to slow down more than
is necessary.
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The material provided on this page is from the FHWA publication
"Pedestrian Facilities User Guide." This guide is currently under review
by practicioners and others in the field. Subsequently, the material
provided on this page is subject to change in the future.
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Purpose:
• Reduces vehicle speeds. Raised measures tend to have the most
predictable speed reduction impacts.
• Enhances the pedestrian environment and pedestrian crossings.
Considerations:
• Do not use if sight distance is limited and/or if the street
is on a steep grade.
• If the street is a bus route or primary emergency route, design
must be coordinated with operators. Usually some devices are acceptable
if used prudently - one device may be appropriate and may serve the
primary need, e.g. if there is a particular location along a street
that is most in need of slowing traffic and improving pedestrian conditions.
• The aesthetics of speed humps and speed tables can be improved
through the use of color and specialized paving materials.
• Noise may increase particularly if trucks use the route regularly.
• May create drainage problems on some streets.
Estimated Cost:
The cost for each speed hump is approximately $2,000. Speed tables
are $5,000–$15,000, again depending on drainage conditions and materials
used.
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