List of U.S. cities with high transit ridership - Wikipedia
Map: All Subways of North America | 511 Contra Costa
Sunday Open Thread: Urban Rapid Transit Systems of North America – Seattle Transit Blog
Global urban subway development, construction material stocks, and embodied carbon emissions | Humanities and Social Sciences Communications
Openings and Construction Starts Planned for 2020 – The Transport Politic
Subway Maps for Cities without Subways - Urban Omnibus
4 Unique Solutions to America's Failing Public Transportation System | Earth.Org
Cities With Best Public Transportation Systems
The World's Best Subways
China to Tunnel 800 Miles of Subway
The Best Cities for Public Transportation - SmartAsset
Which USA cities have operational subway trains? - Quora
When American transit agencies ignore the world's move to open gangways – The Transport Politic
What the Subway Is Like in 16 Different Cities.
Here's How Tiny Toronto's Subway System Is Compared To Other Subways Around The World - Narcity
In the United States, what cities have subways or somewhat of subways, like not full subways? - Quora
Best US Cities for Public Transportation, Ranked: WalletHub Study
Mapped: historical public transit systems v their modern equivalents | Cities | The Guardian
/cdn.vox-cdn.com/uploads/chorus_asset/file/13610468/11_denver_9.jpg "Which US cities have good and bad public transportation - Vox")
Which US cities have good and bad public transportation - Vox
These North American Cities Have the Best Public Transit Systems
Subway Maps for Cities without Subways - Urban Omnibus
xkcd: Subways
Why don't more U.S. cities have metro systems like New York? - YouTube
