Smart card taps track clogs on London’s Tube

Smart card data are helping to unravel which stations in the London Underground system, above, may be most vulnerable to traffic jams.
Sameboat/Wikimedia Commons (CC BY-SA 4.0)
Smart card data are helping to unravel which stations in the London Underground system, above, may be most vulnerable to traffic jams.
Sameboat/Wikimedia Commons (CC BY-SA 4.0)