<http://schema.org/about>
"20 MPH/30 KPH seems to be a good compromise, with the number of deaths being very small and the number of uninjured victims being more significant, unlike with higher speeds where things are reversed."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/cars/what-should-speed-limit-cars-cities.html>