For the many YPP readers interested in planning and sustainability issues and urban development: Alex Steffen at WorldChanging has a terrific essay on city redevelopment titled "My Other Car is a Bright Green City." It's fairly long for a blog post, but well worth reading, as it summarizes a lot of the current thinking about green tech, density planning, and cities over the past couple of years. (See also David Owen's "Green Manhattan [PDF]," etc.)

A brief summary of Steffen:

1) Since most of the energy consumed and CO2 produced happens in the home, we should focus on how people live and work rather than (solely) the gas efficiency of the car they use to get there.

2) We need to act fast, not just because our lifestyles are out of control, but that the rest of the world emulates us.

3) This doesn't mean cars aren't important, just that tailpipes and MPG matters less than the enviro (and social!) costs of roads and infrastructure, commuting, etc.

4) If we want to turn this around, we have to promote and build denser housing developments and leverage existing high-density neighborhoods (i.e. cities and inner-ring suburbs.

5) We can do this faster and achieve higher energy gains than we can turn around the existing automotive fleet.

6) Goodies! Bike shares, transit-oriented development, New Urbanist neighborhoods. A green-city-geek's geekstuff.