Traffic calming and fact checking

I had just about missed Michael Mccarthy’s Courier piece on traffiic calming until it popped up on a listserv.   He’s taken a contrarian view for effect, I think, suggesting twice that we really don’t know whether traffic calming works.

Although traffic calming continues to expand in Vancouver, long-term beneficial results remain impossible to ascertain because no studies have been done.  Initially, the societal benefits were supposed to reduce collision frequency and severity, increase the safety for non-motorized users of streets, enhance the street environment and increase the quality of community life.

Now really, you simply can’t write that kind of thing in the age of search engines without at least checking.  It took me literally 15 seconds to find this on Google Scholar, the first item that popped up:

Area-wide urban traffic calming schemes: a meta-analysis of safety effects.

Institute of Transport Economics, Oslo, Norway. rune.elvik@toi.no

This paper presents a meta-analysis of 33 studies that have evaluated the effects on road safety of area-wide urban traffic calming schemes. …

The meta-analysis shows that area-wide urban traffic calming schemes on the average reduce the number of injury accidents by about 15%. The largest reduction in the number of accidents is found for residential streets (about 25%), a somewhat smaller reduction is found for main roads (about 10%).  Similar reductions are found in the number of property damage only accidents.

The results of evaluation studies are robust with respect to study design. There is no evidence of publication bias in evaluation studies. Study findings are found to have high external validity.

As for the effects of early traffic-calming initiatives on the quality of community life in Vancouver, maybe this might help.