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Neighborhood Traffic Management Program (NTMP)

Tools to Address Traffic Volumes and Reducing Vehicle Collisions

Traffic Circles(RoundAbouts)

Top view of a street with a traffic circle

Traffic circles are intersections with central circular islands and a circular one-way roadway around the island Drivers yield to vehicles already circulating within the intersection.

They are self-enforcing and can improve safety due to the replacement of vehicular crossing movements with merging movements. Design standards are strict and primarily originate from the UK and Australia. They can help beautification projects if the central island is planted.

Culver City, CA

Traffic circle temporary installation

Temporary Installation

Alhambra, CA

Traffic circle permanent installation

Permanent Installation

PROS

  • Speed reduction possible.
  • Self-enforcing.
  • Provides opportunity for roadway beautification.
  • Reduces accidents in many cases.
  • Creates less delays.
  • Can accommodate all vehicles if correctly designed.

CONS

  • Difficult for cyclists to use.
  • Can be difficult for pedestrians.
  • Needs to be properly designed.
  • Needs to be well illuminated.
  • Uneven entry volumes can reduce effectiveness.
  • May cause initial confusion for drivers.
Summary of Effectiveness
Volume Reduction Possible
Speed Reduction Yes
Safety Improvement Yes (Cars)
Streets to Use On Collector, Local Any
Use on Bus Route Yes
Use with Curbs and Gutters Yes
Spot or Area-wide Use Spot
Emergency Service Access Issues No
Impacts on Arterials N/A
Change in % Truck Unknown
Environmental Changes Unknown
Dependence on enforcement No
Level of Violation N/A
Aesthetics and Landscaping Landscaping