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Traffic Calming Measures

The Transportation Division addresses traffic concerns using a variety of physical and non-physical devices depending on the issue(s), resources and community support.  

Download the Traffic Calming Measures Photo Guide to view examples of many calming measures described below. 

Signage/Striping/Enforcement Measures (Non-Physical)

  • Neighborhood Signs – Neighborhood entrance identification signs help drivers to understand they are entering a neighborhood and should therefore drive responsibly.
  • Warning Signs – Such as a "curve ahead" sign alerts motorists of a roadway condition change.
  • Stop Signs – Stop signs may be placed to control traffic at intersections. May reduce collisions.
  • Speed Limit Legend – The speed limit may be painted onto the roadway, at the entrance to the neighborhood from a major street, to alert motorists of a change in speed limit.
  • Striping – striping is added to streets to visually narrow the lane and alert drivers of pedestrians and bicycles.
  • Bicycle Lanes – Bicycle lanes may be established to promote bicycle use and safety.
  • Botts Dots with reflective markers – Botts dots and reflectors are used in combination to keep drivers on the right side of the road, especially useful on curves.
  • Crosswalks – depending on the need, there are a variety of crosswalk options that may be used at intersections to identify the safest place to cross.
  • Visibility Issues – Brush and trees may be trimmed to improve visibility.
  • Parking Modifications – Parking areas may be adjusted to improve visibility or narrow lane widths.
  • Radar Trailers – Radar trailers are used to educate motorists of their driving speed and encourage speed limit compliance.
  • Targeted Police & Parking Enforcement – extra attention given to the neighborhood by police and parking enforcement officials in matters of traffic calming and enforcement of parking procedures.

Vertical Deflection Measures (require vehicles to travel up and down)

  • Speed Humps – Humps in the roadway that motorists must slow down to pass over. Not approved on Regional Transit or emergency response routes.
  • Speed Lumps – Approved for Regional Transit and emergency response routes. Allows buses and emergency vehicles to straddle a hump instead of going over it.
  • Speed Tables – A flat-topped speed hump. Used on streets with posted speed of 30 mph or less. Approved for Regional Transit and emergency response routes.
  • Raised Crosswalks – Raised crosswalks channelize pedestrian crossings, providing pedestrians with a level street crossing. Also, by raising the level of the crossing, pedestrians are more visible to approaching motorists.

Horizontal Deflection Measures (require vehicles to travel left to right, or right to left)

  • Traffic Circles – a raised circular island in the center of an intersection, diverting motorists slightly from their paths. Narrow field of vision. May reduce number of collisions at intersection.
  • Chicanes – Alternating curb extensions at regular intervals used to narrow the traveled way. Protects parking.
  • Striped/Raised Islands – Striped or raised islands are used to separate opposing lanes of traffic or channel vehicles at intersections.

Narrowing Measures (narrow the vehicle travel lane)

  • Bulb Outs – Bulb-outs are installed at intersections and narrow the street by widening the sidewalk or the landscaped parking strip at the curb.
  • Chokers – Chokers are installed mid-block and narrow the street by widening the sidewalk or the landscaped parking strip at the curb.
  • Pedestrian Islands – Pedestrian islands are small islands in the middle of the street that serve to narrow vehicle travel lanes, provide a visual narrowing of the roadway, and give pedestrians a refuge when crossing the street. They can be installed mid-block or at intersections, made of concrete or landscaped.
  • Slow Points – Slow points are small islands in the middle of the street that serve to narrow vehicle travel lanes and provide a visual narrowing of the roadway. They are installed at mid block and can be landscaped.
  • Entry Islands – Entry islands are small islands in the middle of the street that narrow vehicle travel lanes. They are installed at the entrance to a street.

Diversion Devices

These devices are more costly and may require an environmental review, extensive community involvement and vote by the City Council for approval and are generally only considered if the methods above will not achieve the goal(s) for the particular project.

  • Diverters – Diverters direct traffic flow at an intersection, prohibiting specific movements. Narrows field of vision for driver.
  • Half Street Closure – Half-street closures are located at intersections and limit access to a street by preventing specific movements.
  • Full Street Closure – Full street closures divert traffic by closing a street to directional or all through traffic.
  • One Way/Two Way Operations – One way/two way operations change streets from one way to two way traffic or from two way to one way traffic.