Curb extensions are narrowing of the roadway curb line either through physical extension of the existing curbs, construction of smaller islands adjacent to the curb or installation of painted and signed off areas of the road intended for pedestrians and bicyclists only. The intent behind curb extensions is to physically narrow the drivable portion of a road and thus shorten the crossing distance for pedestrians. Curb extensions may also produce a calming effect on vehicular traffic speeds. Extensions are usually installed at intersections but they can be installed mid-block as well and are typically installed with a marked crosswalk and additional signs to alert drivers of the narrow road conditions. Depending on the roadway cross slope, curb extensions may affect surface drainage so caution should be used in what type of extension to install.
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