And, boo, no it doesn’t include Canada.  But it’s another big step:

Today we’re announcing our first ranking of of U.S. city transit systems based on residents’ access to public transportation.

To compute our rankings, we calculated the Transit Score of over 1 million locations in the largest 25 cities that provide open public transit data.

Transit Score measures how well a location is served by public transit by assigning a “usefulness” value to nearby transit routes based on frequency, route type, and distance to the nearest stop on the route.  Type an address into Walk Score to get your personal Transit Score.

City scores are calculating by applying the Transit Score algorithm block-by-block throughout the city using a population-weighted methodology.

No. 1, with a Transit Score of 81, is New York City. Duh. 

New York City 30 Minute Transit Shed

Second, at 80, is San Francisco.  And so on.

They also add some fun facts:

Did you know:

• Riding public transportation saves individuals on average over $10,000 a year.
• Americans took over 10 billion trips on public transportation in 2011.
• The average annual number of vehicle miles traveled by young people (16 to 34-year-olds) in the U.S. decreased 23 percent between 2001 and 2009.

UPDATE:  Jarrett Walker critiques Transit Score.  He can’t recommend it.