Neckdowns and bulbouts reduce the crossing width of streets for pedestrians, make pedestrians more visible in a crosswalk, and add space to sidewalks that can be used for pedestrian amenities and activities - which is why they are now common in downtown projects. By forcing drivers to slow down when they turn the corner, makes it safer and more comfortable for pedestrians. Research shows they have a minor impact on traffic speed.
"Center island narrowings are raised islands located on the centerline of a street that narrow the travel lanes at that location. They are also called mid-block medians, median slow points, or median chokers. They often are nicely landscaped to provide visual amenity and neighborhood identity."
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Traffic Calming: State of the Practice
Excerpt
Cross-Section Elements: Curbs There are two types of curbs: barrier and mountable. Both in urban and suburban environments curbs serve functions such as drainage control, roadway edge delineation, and right-of-way reduction.
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Flexibility in Highway Design
Case Study
Main Street - Littleton, NH Littleton, NH
This town of 6,000 serves as a regional center and recently used "placemaking" to develop new concepts with the community and NHDOT for a total reconstruction of Main Street starting in 2005. CSS experiments were used to test the validity and acceptability of potential changes.
Case Study
Downtown Revitalization, Safety & Congestion Improvements, SR-14 - Bingen Bingen, WA
The purpose of this project was to reduce traffic congestion through this section of SR-14, which improved safety and traffic flow (mobility). The city of Bingen needed economic revitalization of the downtown corridor, and anticipated that their efforts to improve the transportation system would result in improved economic vitality.
Case Study
San Bernardino San Bernardino, CA
"...a vision for the rebirth of downtown San Bernardino, one that builds upon the steady progress of a revitalization effort already in the works and that directly responded to the needs the community revealed."
Case Study
New York City, Mulry Square New York, NY
Sidewalk extensions, reconfigured crosswalks, and additional greening of the area have helped transform this intersection that was known for pedestrian accidents and high-speed turns. Sidewalk extensions were painted on the street in the short term and outlined with temporary bollards to test the impact of the recommendations on traffic flow. Once it was clear that the solutions worked, the project was built out in final form, with slate pavers, granite curbs, new crosswalks, landscaping, bollards, and changes in traffic light phasing. Capital construction was completed in 2001.
Case Study
Bulbouts in Anderson, SC Anderson, SC
Downtown Anderson, South Carolina features landscaped sidewalk extensions with inset diagonal parking, in addition to paved sidewalks and crosswalks.
Case Study
Bulbouts in Encinitas, CA Encinitas, CA
Landscaped sidewalk extension with a bench and a mosaic trash can. This treatment was given to intersections along historic Route 101 with attention to details, and public art.
Case Study
Bulbouts in Birmingham, MI Birmingham, MI
Birmingham has added sidewalk extensions to many of its street corners, some of which include landscaping and small planters.
Case Study
Bulbout: Cotati, California Cotati, CA
This sidewalk extension is under construction on Old Redwood Highway, a two-lane road in a small rural town.
Case Study
Bulbout : Del Ray Beach, Florida Del Ray Beach, FL
Planted sidewalk extension with inset parallel parking on a commercial street.
Case Study
Bulbouts in Easton Town Center in Columbus,OH Columbus, OH
In Easton Town Center sidewalk extensions have been added to many streets along with inset parking, and a number of sidewalk amenities including contextual lights, trash receptacles, signage, bollards, landscaping, a kiosk, and chairs and tables.
Case Study
Bulbouts in Davis, CA Davis, CA
Planted sidewalk extensions were added by developer of a mixed-use building on C Street near the Farmers Market.
Case Study
Through Road in Gerderath, Nordrhein-Westfalen, Germany Gerderath,
"In Gerderath two of the intersections have been rebuilt - resulting in positive visual and speed reducing effects. One intersection now has a raised area, the other has been converted to an asymmetrical roundabout."
Case Study
Odense Town Center, Denmark Odense,
"In connection with Odense's 1000th years' anniversary in 1988 a number of new developments were inaugurated in the town centre: pedestrian streets, a bus street, and a bicycle route network. This has given the already lively town centre a significant lift, has stimulated the activity in the area, and has markedly improved the visual environment."
"Traffic engineers are always talking about enhancements in terms of 'trade-offs', but it's not a trade off to add landscaping and curb extensions and make the street safer for pedestrians and drivers alike. Even if improving the road for all users increases commuting time through Main Street by a minute, let's call it a value, not a trade-off."
"Neckdowns are curb extensions at intersections that reduce roadway width from curb to curb. There are sometimes called numbs, bulbouts ,knuckles, or intersection narrowings. If coupled with crosswalks, they are referred o as safe crosses. Neckdowns are the most common type of street narrowing."
