Pedestrian Safety Guide and Countermeasure Selection System


This curb extension at an intersection shortens the crossing distance for pedestrians and creates space for landscaping. - Carl Sundstrom

Living Streets Page 7-13 Curb extensions improving the ability of pedestrians and motorists to see each other.
Living Streets Page 7-13


Living Streets Page 5-7 A combination of curb extensions and a median refuge narrow the roadway, reduce the pedestrian crossing distance, and reduce the time that pedestrians are in the street.
Living Streets Page 5-7 - Kristen Brookshire Interim curb extensions can be installed using pavement markings and flexible delineator posts as shown in this image from Memphis, Tennessee. - Kristen Brookshire - Dan Burden Curb extension in a residential setting. - Dan Burden

Curb Extensions

Curb extensions—also known as bulb-outs or neckdowns—extend the sidewalk or curb line out into the parking lane and reduce the effective street width. Curb extensions must not extend into travel lanes and should not extend across bicycle lanes. This countermeasure improves pedestrian crossings by reducing the pedestrian crossing distance, reducing the time that pedestrians are in the street, visually and physically narrowing the roadway, and improving the ability of pedestrians and motorists to see each other. Curb extensions also create space for the addition of a curb ramp.

Motorists are encouraged to travel more slowly at intersections or midblock locations with curb extensions, as the reduced street width sends a visual cue to motorists. Turning speeds at intersections can be reduced with curb extensions (curb radii should be as tight as is practicable). Additionally, curb extensions placed at an intersection essentially prevent motorists from parking in or too close to a crosswalk and from blocking a curb ramp or crosswalk. Motor vehicles parked too close to corners present a threat to pedestrian safety, since they block sightlines, obscure visibility of pedestrians and other vehicles, and make turning particularly difficult for emergency vehicles and trucks.


Wide roadways can create difficult crossing situations for pedestrians. Not only do pedestrians need more time to cross the roadway, but the roadway width encourages motorists to speed or take turns quickly. Curb extensions improve safety because they increase visibility, reduce speed of turning vehicles, encourage pedestrians to cross at designated locations, shorten the crossing distance, and prevent vehicles from parking at corners.


• Curb extensions are only appropriate where there is an on-street parking lane and where transit and bicyclists would be traveling outside the curb edge for the length of the street. They should not extend more than 6 feet from the curb.
• The turning needs of larger vehicles, such as school buses and emergency vehicles, need to be considered in curb extension design, especially at intersections with significant truck of bus traffic. However, speeds should be relatively slow in a pedestrian environment so all vehicles should be traveling at speeds conducive to tight turns.
• Emergency access is often improved using curb extensions if intersections are kept clear of parked cars. Fire engines and other emergency vehicles can climb a curb where they would not be able to move a parked car. At midblock locations, curb extensions can keep fire hydrants clear of parked cars and make them more accessible.
• It is not always necessary for a roadway to be designed for a vehicle to turn from a curb lane to a curb lane. Vehicles can encroach into adjacent lanes safely where volumes are low, or speeds are slow.
• Curb extensions can create additional space for curb ramps, landscaping, and street furniture that are sensitive to motorist and pedestrian sightlines; this is especially beneficial where sidewalks are otherwise too narrow. Care should be taken to ensure that street furniture and landscaping do not block motorists’ views of pedestrians.
• Curb extension design should facilitate adequate drainage.

Estimated Cost

The cost of a curb extension can range from $2,000 to $20,000, with an average of $13,000 each, depending on the design and site condition. Storm water management impacts, transit stops, large areas, special pavement, street furnishings and planting, and moving utility poles or controller boxes can significantly increase increase the cost. Retrofitting an existing curb extension by adding vegetation can be relatively inexpensive.

Safety Effects

A summary of studies that have looked at the safety effects of curb extensions can be found here.

Case Studies

Cambridge, MA
Berkeley, CA
Eureka, CA
Fort Plain, NY
Oneonta, NY
Tempe, AZ
Fort Pierce, FL
West Palm Beach, FL
Cambridge, MA
Bellevue, WA
Portland, OR
Arlington County, VA
El Cajon, California
Bethesda, Montgomery County, MD
Portland, OR
Corvallis, OR
Hendersonville, North Carolina
Village of Great Neck Plaza, New York