Friday, September 16, 2011


A few years ago any suggestion of enabling towns to set speed limits under 25 mph quickly found the legislative waste basket--today the City of Burlington, VT starts the process of setting the maximum speed on all streets of 25 mph and the business district 20 mph (two streets excepted with a 30 mph limit).

The reason for lowering urban speed limits comes from the desire to improve walker safety--30 mph is the speed where the chance of surviving is a 50-50 proposition and at 20 mph walkers survive over 90% of the time.  All the traffic calming imported from Europe over the last two decades apparently brought a public opinion shift to the belief that speeds can be reduced in a way that does not cause much discomfort or hassle for drivers while bringing lots of comfort and ease of moving through busy intersections to those on foot.

Still, North American walker injury rates per mile of travel remain several times higher than those in urban Netherlands and Germany in a study by John Pucher of Rutgers University.  A key treatment, the emerging modern roundabout, reduces injuries by up to 90% while reducing delay for all users--another key encouraging citizens and public works folks that yes, you can improve walking and car traffic at the same time.  (The roundabout also cuts serious injuries for car occupants by 90%.)  The critical feature of the roundabout comes from its design which forces vehicles to slow speeds.  

 Still there exists another plateau for speed management which can be applied to lower volume streets including most residential areas and town and city centers, a speed limit of 0-10 mph.  This type of speed context already exists at the three cross streets at Burlington's Church Street Marketplace, including Cherry Street where upwards of 100 buses cross from the transit terminal just west of the Marketplace.   Europe already features this next plateau, termed "shared space" and in the U.K. "naked streets" where the low 0-10 mph speeds allow mixing of all modes with the safest movement for all users.  The "shared space" style design further features a total absence of signs and traffic signals. 

So, the new walking renaissance can now begin and Burlington soon be joined by hundreds of urban areas can move to impose the much slower vehicle speeds needed for the safety and comfort of those who walk the streets.