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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-05-124
Date: July 2006

Lesson 20: Traffic Calming

Picture shows a street that has various traffic calming elements, including curb extensions and chicanes.

Photo Source: PBIC, www.pedbikeimages.org

Lesson Outline

  • Need for traffic calming.
  • Goals and objectives of traffic calming.
  • Traffic calming issues.
  • Types of traffic calming devices.

Need for Traffic Calming

  • Cut-through traffic.
  • Relatively high speeds in neighborhoods.
  • Determine the source of the problem.
    Why do people cut through neighborhoods?
    • Traffic backup on main route.
    • More direct connection.
    Why do people speed?
    • Make up time due to delay on main route.

Need for Traffic Calming

In this diagram, traffic on a major arterial is congested at an intersection due to faulty signal timing, and cars opt to detour though minor roads adjacent to the major roadway, causing a traffic calming need.

Goals and Objectives of Traffic Calming

  • Increase safety by slowing vehicle speeds.
  • Improve street feel.
  • Enhance aesthetics.
  • Reduce crime.
  • Provide a balance among modes.
  • Slows vehicle speeds.
  • Increases safety.
  • Accommodates motor vehicles.

Traffic-Calming Issues

  • Safety.
  • Impact of traffic operations.
  • Lack of proven design standards.
  • Liability.
  • Emergency/service vehicle access.
  • Impacts on bicycling.

Traffic-Calming Treatments

This diagram shows a plan for five blocks across and four blocks down and various traffic calming treatments incorporated at several intersections and corridors: curb extensions, neck downs, traffic circles, diverters, chicanes, and cul-de-sacs.

Types of Traffic-Calming Devices

  • Raised pavement areas.
  • Reduced street area.
  • Street closures.
  • Traffic diversion.
  • Texture and visual devices.
  • Parking.

Combination Devices

  • Woonerf.
  • Entry treatments.
  • Slow streets.
  • Channelization.
  • Traffic calming on major roads.
  • Modified intersection design.

Lesson Summary

  • Traffic calming is a viable alternative for having different types of transport share the street.
  • There are many types of traffic-calming devices and strategies from which to choose.



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