Best Practice Category:
Traffic calming strategies are a combination of physical measures intended to improve traffic safety for all users of the roadway including pedestrians, bicyclists, and transit. These strategies typically involve some form of physical roadway improvement that slows vehicular travel speeds and/or traffic volumes, while reducing collision frequency and severity as well as improving safety for non-motorized users of the street.
Traffic calming strategies can help play a significant role in facilitating the success of TODs, as first and last mile connections to transit typically involve some form on non-motorized travel. The decision to utilize transit is heavily impacted by the perception of safety. Thus, street designs that control vehicular travel speeds and volumes to enable the safe and efficient movement of non-motorized travel can significantly increase the attractiveness of transit and TODs.
Best practices in traffic calming strategies vary depending on street type and the function that they serve, however, some common traffic calming strategies include the following:
- Roundabouts: circulating roadway that encircles a landscaped central island
- Neighborhood traffic circles: small circles to control vehicle speeds within a neighborhood
- Curb extensions: extension of the sidewalk into the parking lane; provides additional pedestrian space at key locations
- Chicanes: series of mid-block curb extensions or islands that alternate from one side of the street to the other to form s-shaped curves in a roadway
- Road diet: reduction of the number of travel lanes or the width of the road; calms traffic while freeing up space for turn lanes, bus lanes, pedestrian refugee islands, bike lanes, sidewalks, bus shelters, parking or landscaping.
- Raised intersections: intersections that are flush with the sidewalk; bollards at corners are used to keep motorists from crossing into the pedestrian space
- Raised crosswalks: crosswalks that at raised to the level of sidewalks, creating a speed table for vehicles to slow down
- Speed humps: rounded raised pavement that extends across the roadway
- On-street parking: parking along the curb of the street
- Textured or colored pavement materials: brick, concrete pavers, and stamped asphalt; used in visually attractive ways to highlight awareness of a traffic-calmed area
- Median/Pedestrian refuge: protected islands in a crossing where people may safely wait for incoming traffic while crossing the street
- Improves safety for all roadway users
- Improves conditions for non-motorized modes of travel
- Improve connectivity by increasing street crossings
- Increase space dedicated to transit users and non-motorized travel
- Improve comfort for non-motorized users
- Decrease through-traffic
A road diet was completed on Broadway and 3 rd Avenues of the downtown corridor on April 2011. A traffic lane was removed in each direction of travel and bicycle lanes were added. These changes calmed traffic and made the area friendlier to bicyclists and pedestrians alike. The project received strong political, municipal, business, and citizen support—ultimately contributing to its successful completion.
A road diet was completed on Cordova Street between Lake Avenue and Hill Avenue on June 2010. The city used funds from the American Recovery and Reinvestment Act to perform a basic repaving project to install bicycle lanes and enhance existing curb parking. The project was motivated by previous safety and traffic concerns, particularly for bicyclists and pedestrians crossing the street. The project supported the city’s Bicycle Master Plan, making it safer for bicyclists travelling between South Lake District and Pasadena City College. The project was specifically successful in increasing safety through reducing automobile speeds and increasing bicycle ridership.
The Michigan Avenue Neighborhood Greenway was completed by the City of Santa Monica in 2015. The Greenway enhances Michigan Avenue to promote use of the street by bicyclists and pedestrians. Michigan Avenue provides a key east-west connection through the central portion of the city, connecting the surrounding neighborhoods to Santa Monica High School, the Civic Center, and the new Bergamont Exposition Light Rail Station. Project elements included traffic circles, increased landscaping, and improved pedestrian facilities.
The San Francisco Municipal Transportation Agency (SFMTA) implemented a traffic calming pilot project on local streets adjacent to Marshall Elementary school, which is located within a half mile radius of the 16 th Street BART Station. The goals of the project were to reduce motor vehicle speeds and to create a more walkable and bikeable neighborhood. The site was selected for the pilot project based on a number of factors such as high traffic speeds, volumes, collision history, and proximity to pedestrian generators and attractors.
The pilot project re-engineered the streets in the area to reduce vehicle speeds and volumes through the introduction of speed humps, edgelines, raised crosswalks, road diets, and curb extensions. The study evaluated before and after traffic speeds and volumes to determine whether or not the traffic calming measures helped the City achieve its goals for the project. Results of the pilot project indicated that on average motor vehicle speeds decreased and were below 20 mph. Additionally, pedestrian volumes in the project area increased by an average of 20%. Local jurisdictions seeking an understanding of how pilot projects in traffic calming can be implemented may find the details of this report useful in implementing their own pilot projects and traffic calming measures.
The City of San Ramon developed its Residential Traffic Calming Program (RTCP) to coordinate the collaboration of city staff and residents to improve traffic safety throughout the city. The program allows residents to formal request the implementation of effective traffic calming measures throughout the neighborhoods of San Ramon. The program establishes a single point of contact for residents concerned about traffic safety, travel speeds and volumes in their neighborhoods.
The program is broken out into two phases, the first phase focuses on educating residents on the appropriate tools available for achieving various goals in traffic safety and temporary traffic calming measures that are available. These include, but are not limited to neighborhood information plans, radar trailer, passive traffic controls, and pavement markings. If traffic safety issues still exist, then more permanent measures are considered, such as speed humps, traffic circles, chockers, and median barriers.
Other tools, toolkits, resources, or manuals that influence or relate to this tool
- The Model Design Manual for Living Streets provides an in-depth chapter on Traffic Calming Measures, including when and where each type of measure is appropriate.
- Federal Highway Administration (FHWA) - Traffic Calming
- Institute of Transportation Engineers (ITE) – Traffic Calming
- NACTO – Urban Street Design Guide
- NACTO – Urban Bikeway Design Guide
- Traffic Calming 101 from the Project for Public Spaces