The following responds a reference by a Burlington Walk Bike Council to a U.K. paper advocating walking and bicycling for attaining better public health. My response to that suggestion follows...
The better question is "what about the U.K. and North America." The U.K., U.S. and Canada (more U.S. and Canada) record far lower walk/bike rates, particularly in the bike department than typical European nations where walk/bike urban numbers often hit 20-30% while the U.S, and Canada remain bottom feeders at about 10% walk and 1% bicycle.
As far as Burlington [VT] is concerned the Marketplace with its shared space intersections nears Nirvana territory. But "routes to the marketplace" reflect the kind of desperate conditions which make our non-Marketplace areas in the typical category of a a few hundred percent greater walk casualty rates and bicycle casualty rates per mile of travel compared to German and Netherlands as Rutgers Jean Pucher reported in an extensive paper devoted to the very subject you bring forward, health and walking and bicycling published in the American Journal of Public Health in 2003--it is a landmark study
Pucher did further work in this area showing incidence of obesity, diabetes, etc. versus proportion of walking and bicycling modes [in several nations] with the expected results.
Am J Public Health. 2010 Oct;100(10):1986-92. Epub 2010 Aug 19.
But the problem we face comes in great part--not that we do not have sidewalks in Burlington or some (but not enough) bikeways of various types--the problem lies in essentially unsafe intersections where signals kill, injure, DELAY, pollute and uglify. Until we unplug the major intersections so that one, for example, cross arterials with little delay (think Battery, Main, Pearl, Winooski, North, etc.) then encouraging folks to walk amounts to choosing your poison.
Roundabouts--probably because they traffic calm a block or two on all legs--have that peculiar feature that the more you build the safer they all become. Anything but a roundabout on average generates about a 900% greater rate....[of] serious injuries and fatalities--like Sam Lapointe in January [walker killed at a signalized Burlington intersection]. To be an advocate for walking and health, you have to be an advocate for roundabouts along all urban walking corridors. Of course, roundabouts bring major improvement in car occupant safety too--think of Karen Borneman at St. Paul and Main just two years ago now [young woman killed in a T-bone two-car crash at the intersection about 150 feet from Burlington City Hall].
So the task is clear--prioritize the conversion of intersections to roundabouts so as to enable more walking and bicycling in a safe environment.