Description:
- long raised speed humps with a flat section in the middle and ramps on the ends;
sometimes constructed with brick or other textured materials on the flat section
- sometimes called flat top speed humps, trapezoidal humps, speed platforms, raised
crosswalks, or raised crossings
Applications:
- local and collector streets
- main roads through small communities
- typically long enough for the entire wheelbase of a passenger car to rest on top
- work well in combination with textured crosswalks, curb extensions, and curb radius
reductions
- can include a crosswalk
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Design/Installation Issues:
- typically 22 feet in the direction of travel with 6 foot ramps on each end and a 10
foot flat section in the middle; other lengths (32 and 48 feet) reported in U.S. practice
- most common height is between 3 and 4 inches (and reported as high as 6 inches)
- ramps are typically 6 feet long (reported up to 10 feet long) and are either parabolic
or linear
- careful design is needed for drainage
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Potential Impacts:
- no effect on access
- speeds are reduced, but usually to a higher crossing speed than at speed humps
(typically between 25 and 27 miles per hour)
- traffic volumes have been reduced on average by 12 percent depending on alternative
routes available
- collisions have been reduced on average by 45 percent on treated streets (not adjusted
for traffic diversion)
- reported to increase pedestrian visibility and likelihood that driver yields to
pedestrian
Emergency Response Issues:
- typically preferred by fire departments over 12 to 14-foot speed humps
- generally less than 3 seconds of delay per hump for fire trucks
Typical Cost:
- approximately $2,500 (in 1997 dollars) for asphalt tables; higher for brickwork, stamped
asphalt, concrete ramps and other enhancements sometimes used at pedestrian crossings
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1627 I ("Eye") Street, NW, Suite 600
Washington, DC
20006-3538 USA
Phone: 202-785-0060
Fax: 202-785-0609
Send comments to:
ite_staff@ite.org
SPEED HUMP | SPEED TABLE | RAISED INTERSECTION | CLOSURE | NEIGHBORHOOD TRAFFIC CIRCLE | CHICANE | CHOKER | CENTER ISLAND NARROWING
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