Alex Steffen from Worldchanging has written a good post on why he believes building compact communities should be one of America's highest environmental priorities. he also asks 'why, in fact, our obsession with building greener cars may be obscuring some fundamental aspects of the problem and some of the benefits of using land-use change as a primary sustainability solution':
Read full post - 'My Other Car is a Bright Green City'
Some people make the argument that the built environment is much harder to change than the design of cars -- after all, don't we buy a new car every few years and a new home at most a few times in our lives? But the reality is not so clear.
Generally, we think of cars as things which are quickly replaced in our society, and buildings as things which rarely change. But that will not be the case over the next few decades. Because of population growth, the on-going development churn in cities (buildings remodeled or replaced, etc.), infrastructure projects and changing tastes, we'll be rebuilding half our built environment between now and 2030. Done right, that new construction could enable a complete overhaul of the American city.
This is especially true since we don't need to change every home to transform a neighborhood. Many inner-ring suburban neighborhoods, for instance, can become terrific places simply by allowing infill and converting strip-mall arterials to walkable mixed-use streets. This transition can happen in a few years.
In comparison, I've been told that it takes at least 16 years to replace 90% of our automotive fleet, and since it takes years to move a design from prototype to production, it looks likely that the cars most people in the US have available to them to drive in 2030 will not be all that different from the more efficient cars today