Here’s an interesting tidbit from the ever-geekalicious Todd Litman: a chart comparing average impervious surface per household in urban vs. suburban settings.
As you can see, large single-family lots—the sort of homes that are surrounded by greenery—actually require the most pavement overall, particularly for roads. And while dense cities are typically plastered with concrete, in the final analysis urban high-rises are lightest on the landscape.
This chart was taken from a new “Pavement Busters Guide” (pdf link) with some pretty detailed recommendations for ways to reduce impervious surface in cities and suburbs. Todd’s number one recommendation: Educate Decisionmakers. Sounds like a smart first step to me.
Large-lot single fam also has larger semipervious per capita – the expanse of grass is semipervious and has a darker albedo, increasing the Urban Heat Island effect (more here).