Smart Growth & GHGs -- No Clear Link! Really!
June 9, 2011 at 10:45AM How Smart Growth Reduces Emisstions, Sustainable Cities Collective, 060911
And why are people still attempting to refute the irrefutable? Short term gain can be the only rational reason.
Rob writes that the flaw in NAHB’s analysis is that they looked only at the density of residential development, in isolation from other relevant factors:
“If all you do is bring people closer together, you get modest reductions in gasoline consumption. But if you do all of the other things associated with smart growth — that is to say, create a walkable environment with multiple destinations and alternative modes of transportation — the impacts on VMT, energy use, and greenhouse gas emissions are huge.
That is true as far as it goes, but I would go further to clarify the most important factor of all is what transportation researchers call regional accessibility (sometimes also called "destination" accessibility), or the location of a place within a region. The more central a place is to the region, or to a strong suburban center, the lower the VMT, in large (though not exclusive) part because driving distances become shorter.
In Ewing and Cervero's exhaustive study of the published literature, they found that such locations are as significant in reducing driving rates as the next two significant factors (street connectivity and mixed land use) combined. (See graph above comparing the significance of five major factors.) As Todd Litman puts it, “residents of more central neighborhoods typically drive 10-30 percent fewer vehicle miles than residents of more dispersed, urban fringe locations.”
