A diverter that allows bicycle access

A diverter is an island built at a residential street intersection that prevents certain through and/or turning movements. Diverters affect people living in the neighborhood more than anyone else. Therefore, diverters should be considered only when less restrictive measures are not appropriate.

There are four types of diverters:

  1. Diagonal—breaks up cut-through movements and forces right or left turns in certain directions.
  2. Star—consists of a star-shaped island placed at the intersection, which forces right turns from each approach.
  3. Forced turn—island diverters can be placed on one or more approach legs to prevent through and left-turn movements and force vehicles to turn right.
  4. Truncated—a diverter with one end open to allow additional turning movements.

Diverters must be used in conjunction with other traffic management tools within the neighborhood street network. Any of these diverters can be designed for bicycle and pedestrian access.


Diverters discourage or prevent traffic from cutting through a neighborhood.


  • Consider less restrictive measures first.
  • Impacts residents more than through traffic.
  • Diverters should have strong neighborhood support.
  • Evaluate traffic patterns to determine whether other streets would be adversely affected.
  • Design diverters to allow bicycle, pedestrian, and emergency vehicle access.
  • Diverters generally do not effectively address midblock speeding problems.
  • Diagonal diverters may be used in conjunction with other traffic management tools and are most effective when applied to the entire neighborhood street network.
  • The effect of diverters on service vehicles should be considered.


Costs can range from approximately $10,000 to $51,000 each, depending on the type of diverter and the need to accommodate drainage. On average the cost is around $26,000. More detailed cost information can be found here.