Usage: Pilot
A round traffic island in the center of a traditional intersection. Primarily applicable to lower-traffic intersections as a horizontal speed reduction method for through traffic.
Greeley Avenue and Freeborn Street, Staten Island
Benefits
- Reduces speeds, particularly when applied consistently to an area, while maintaining traffic flow
- Can green and beautify the streetscape with trees and/or vegetation, improving environmental quality
- Inclusion of plantings or art within the island creates an attractive focal point for the neighborhood
Considerations
- May impact underground utilities
- Landscaping requires a partner for ongoing maintenance, including executing a maintenance agreement
- Landscaping must be designed and maintained so that it does not hinder visibility
- Attention should be given to accommodation of and navigation by people with ambulatory and vision disabilities
Application
- Consider at existing stop-controlled intersections, particularly all-way stops
- Consider at intersections of streets with low target speeds (25 mph or below) or low vehicle volumes
- A Roundabout should be considered instead where traffic volumes on intersecting roads are more than 10% of overall traffic volumes
Design
- Design speeds for movement around the circle should be 10 to 15 mph; exit speeds should be limited to 15 mph through the circle’s design wherever possible
- Daylight parking spaces adjacent to the traffic circle to facilitate emergency vehicle and truck access
- Use signs within the center island and reflective materials on the curb to improve center island visibility
- A protective apron of concrete or textured pavement may be provided around the circle to accommodate wide-turning vehicles; where geometric constraints exist and truck volumes are low, trucks may be accommodated by use of a fully mountable roundabout island or allowing left turns in front of the island
- Install approved circulatory signage directing through traffic to proceed to the right of the circle through the intersection
- Locate trees and/or plantings when possible. See Tree Beds and Roadway Plantings in the Landscape chapter
- Where feasible and if there is a maintenance partner, design planted areas to capture stormwater according to current standards. See Stormwater Management Practices in the Landscape chapter
- If work includes tree planting, consider the location of utility infrastructure, including DEP sewers and water mains