20 mph

January 19, 2018, 6am PST
Portland has implemented one of the most sweeping commitments to traffic safety of any city in the United States: 20 mph speed limits over the vast majority of the city's streets.
Streetsblog USA
March 23, 2010, 12pm PDT
Over the last decade, London has established more than four hundred 20 mph zones across the city. The 10mph decrease has had a significant effect on the number of fatalities.
Streetsblog