Neighborhood Traffic Circles

Example of Traffic Circle used in a neighborhood.

Traffic circles can help slow traffic on local and collector streets and calm traffic for pedestrians. While traffic circles are typically not ideal for use at a school crossing location, they can help calm traffic along a street, making the crossing locations on that street safer. Traffic circles typically have less of an impact on emergency vehicles than speed humps or speed tables, and can add to the aesthetics of the street. Neighborhood traffic circles on local streets do not need to have raised splitter islands, but they should be illuminated with streetlights. Landscaping also is important for aesthetics and making the islands visible to motorists. Provisions are needed for maintaining the landscaping and providing water to the landscaping.

Treatment: Neighborhood Traffic Circles

Description/Purpose

Neighborhood traffic circles are raised islands in residential intersections intended to reduce motor vehicle speeds.

Expected Effectiveness

In a study in Seattle, WA, mini-circles were found to reduce motor vehicle crashes by an average of 90 percent.[ITE, 1998] (Institute of Transportation Engineers and the Federal Highway Administration, 1999). They also slowed motor vehicle speeds, reducing the likelihood and severity of pedestrian crashes.

Costs

The cost for a landscaped traffic circle on an asphalt street is about $6,000 and ranges from $8,000 to $12,000 for a landscaped mini-circle on a concrete street [PEDSAFE, 2004].

Keys to Success

  • Keep turning radii tight to avoid compromising pedestrian and bicyclist safety.
  • Accommodate larger motor vehicles by providing a mountable curb on the outer portion of the traffic circle.

Key Factors to Consider

  • Landscaping in the circle should not block sight distance.
  • The needs of blind pedestrians should be considered when determining the design and placement of neighborhood traffic circles.

Evaluation Measures

  • Crashes and injury severity.