Clark, you might find some of the lectures from the University of Melbourne's 2009 Festival of Ideas of interest.

Here, Kvan talks of the effects that land ownership has had on the way in which land is developed into suburbs (particularly reference to a plan for a centre of 800,000 people in Hong Kong territories, all within 800m of the new station)

In another talk, the point was made that urban density and reducing transport needs are more environmentally effective than any number of green buildings. (Although there's no reason you can't have both, of course)

Perhaps this helps: https://www03.cmhc-schl.gc.ca/b2c/b2c/init.do?language=en&shop=Z01EN&areaID=0000000123&productID=00000001230000000062

Greenhouse Gas Emissions from Urban Travel: Tool for Evaluating Neighbourhood Sustainability

Thanks for the tips!!! The problem, I find, is that there are still quite a few studies that look carefully at the relationship between neighborhood design and transportation -- often in the US -- and don't find much. I tend to think that those studies are inconclusive -- perhaps they're looking at the wrong things, or perhaps US cities are just so uniform and sprawling that it's hard to tease out a relationship in a way that satisfies the statisticians. Regardless, those sorts of studies certainly muddy the waters -- which makes white whales harder to spot.

If you read closely, the study cited here actually concluded that the effect of density was not sufficiently large to be effective as a policy tool (and used some very dated data to make the point). That is probably true with respect to density alone (imagine a pod of high-rises in an outlying greenfield).

But density works best in concert with other neighborhood characteristics. And I would add that regional accessibility is perhaps the most important factor that has been studied. Regional accessibility (which measures the distance or travel time between a given location and other important locations/destinations within a metro region) is often associated with neighborhood density, mixed use, transit access, and walkability, so many studies do not segregate the various factors. But those that do (Ewing, Cervero, Walters, etc.) find all five to be individually significant. Neighborhood density coupled with transit, mixed uses, walkability and, especially, a good relatively central location, can be quite powerful in reducing driving and associated emissions. (I have a longer discussion with some links on my own blog from earlier this year for those who are interested.

Kaid -

I did read that, but I simply thought that that particular statement was NOT justified by the rest of their study. As I saw it, they were saying "it's hard to change the average density of existing neighborhoods, so policymakers should pay attention to other things to reduce fuel consumption."

But as zoning boards and regional planning organizations are considering NEW development, this sort of study is still massively important to keep in mind. The *marginal* climate impact of new development will be enormously affected by the form and location it takes place -- whether as compact developments or infill in existing neighborhoods, or as new sparse development on the outskirts of town.

And besides, neighborhood form doesn't change much year to year. But over the long haul -- over the course of decades -- it's among the most important things to get right.