Curb Extension

A curb extension (or also neckdown, kerb extension, bulb-out, kerb build-out, nib, elephant ear, curb bulge,"curb bulb" and blister) is a traffic calming measure, primarily used to extend the sidewalk, reducing the crossing distance and allowing pedestrians about to cross and approaching vehicle drivers to see each other when vehicles parked in a parking lane would otherwise block visibility.

A curb extension is an angled narrowing of the roadway and a widening of the sidewalk (pavement or footway in UK usage). This is often accompanied by an area of enhanced restrictions (such as a "no stopping" or "no parking" zone) and the appropriate visual reinforcement. This is achieved using painted road markings (e.g. lines, coloured areas, or chevrons), barriers, bollards, or the addition of pavement or street furniture (e.g. planters, lamp standards, or benches).

Curb extensions are often used in combination with other traffic calming measures such as chicanes, speed bumps, or rumble strips, and are frequently sited to "guard" pedestrian crossings. In these cases the "squeeze" effect of the narrowed roadway shortens the exposed distance pedestrians must walk.