from google:
link
Traffic Calming Measures - Speed Table
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