April 4


Speed Kidney: The Ultimate in Traffic Calming Devices?

By Mike Spack

April 4, 2017

calming, reduce speed, speed hump, speed kidney, Traffic Calming, traffic speed

By Mike Spack, PE, PTOE

I first wrote about the concept of the Speed Kidney in 2012.  Basically, it’s three speed humps that are parallel to the traveled way that are curved as a chicane per the diagram.  This doesn’t necessarily reduce the average speed very much, but they reduce the number of vehicles driving significantly faster than the design speed.  I like the idea of getting rid of the outlier speeders and clustering traffic at the posted speed limit.

Professor Garcia recently put together a ten minute video that updates the research and covers the results from live installations.  I encourage you to check it out.  I’d really like to see more Speed Kidney’s installed.  Please let me know if you know of any installations outside of Spain.

Mike Spack Bio

  • Mike, in your 2012 article you mentioned the possible challenge of using a speed kidney in a colder area that snowplows have to clear. Have you any further thoughts on how that aspect could be worked out?

  • Plowing: It will be a challenge, but most public works departments in Minnesota have smaller gear (pick up trucks with plows, bobcats, etc) to plow out bumpout parking areas, sidewalks, and other tight spots that a full size plow truck can’t handle. Plowing the speed kidney would obviously be more time consuming than plowing a straight segment of road, but I don’t think it’s a deal breaker. Mike

  • Very interesting, thanks for updating. I wonder if the patent mentioned at the end is filed internationally as well, that would stifle use of it quickly.

  • what will it result in if the driver is not familiar and passes over in a higher speed?

  • We have a speed kidney near 8th Street and Cherry Avenue in Boulder, Colorado, USA.

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    Mike Spack

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