These photos have been making the rounds. Has anyone actually used these on public roads. I doubt it!

The Traffic Engineer for the City of Lakeland [David Uria] has undertaken a survey of Florida municipalities to determine the criteria in use to justify traffic calming meaures. A copy of the results summary is attached.

It’s interesting that they’re generally based on a combination of traffic volume and speeding. There’s general use of a criteria of 85 percentile speeds in the range 5 – 10 mph above the posted speed limits. Traffic volumes vary widely.

The table would be a good starting point for someone drafting traffic calming criteria.

TRAF_CALMING_GUIDELINES_AGENCY_SUMMARY_TABLE_1_2009

My traffic calming site has now been available for several years. It is clear that traffic calming is more than a passing fashion and is now being widely used.

It is less clear, however, which traffic calming measures should be used in any given circumstances; or indeed if any traffic calming is necessary or appropiate. Public officials are often under a great deal of pressure to undertake traffic calming [at sometimes great expense] to address a perceived community problem.

The current state of the art in traffic calming  is in need of criteria or guidelines for when traffic calming is most necessary. Speed humps often yield the ‘most bang for the buck’ and are frequently requested by the public. Criteria for when they are appropriate are needed. To further this debate on the need for traffic calming and ,in particular, speed humps, I am attaching a set of criteria which I drafted and have been in use for several years.

I welcome comment. 

Peter Partington

May 2007

calmingcriteria.pdf