January 14


Steps to Traffic Calming Studies

By Mike Spack

January 14, 2011

TrafficCalmingData I watched the traffic calming webinar sponsored by Traffic Logix yesterday.  Fehr & Peers did a nice job.  One of the bigger takeaways for me was the process they apply to traffic calming projects (traffic calming is the process of applying physical treatments in neighborhoods to reduce the amount of traffic and/or reduce travelling speeds on neighborhood roads).  Here's the typical process they apply to this type of engineering study, with a comment or two added by me –

  1. Collect Data – Traffic volumes, travel speeds, traffic control device locations, crash data, and stop sign compliance.
  2. Observe Existing Conditions – Watch traffic at existing traffic calming treatments already in place in the neighborhood or city to see what works and what doesn't.  Try to find interactions between all modes of travel (pedestrian/bicycle/vehicle).
  3. Present the Toolbox of Traffic Calming Treatments to engaged citizens and policy makers.  TrafficCalming.org is a good resource.
  4. Community Outreach and Agency Coordination – Charrettes are a common way to engage citizens and policy makers to get to the heart of the perceived problem.  Neighborhood surveys, websites, open houses, and walking tours are also commonly used.  It is very important to engage the fire and police departments.  Traffic calming devices slightly degrade response times.  This is a trade-off the policy makers need to weigh.  The fire or police department can derail the whole process if they aren't part of the process and on board.
  5. Recommend Improvements – Often a phased approach is recommended.  Start small and layer on measures until the desired outcome is achieved.
  6. Implementation – Residents often don't like these measures after they are built (they don't realize the pain of driving over speed humps five times a day until they are implemented).  It is wise to do a trial run with temporary installations.  Traffic Logix sells a lot of temporary, rubber products for this purpose.  Cones and barrels can be used for some of the treatments, but they don't do as good a job of simulating traffic circles, bumpouts, etc.  Traffic Logix did sponsor the webinar, but using their products is a good idea. 
  7. Follow-up – Collect "after" data to determine how well things are working.  Changes may need to be made.  This can be an iterative process.  Before/after data is also useful to define local effectiveness of different treatments for future projects.
  • Mike,
    Excellent summary on Traffic Calming. I would recommend that adjacent streets be included in the before and after studies as we frequently find that calming one street often moves the problem to an adjacent street.

  • Amy,
    Great addition! I’ve had first hand experience with traffic calming moving the problem to an adjacent street instead of solving the problem.

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    Mike Spack

    My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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