<http://schema.org/about>
"We have always known intuitively that people who live downtown drive less, but this graph shows how dramatic the effect actually is: If you live in a single family detached house you are likely to drive 15,000 miles per year; if you live in townhouses"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/sustainable-product-design/graph-of-the-day-driving-vs-residential-density.html>