Beyond the Surface: Why Cities Invest Billions in Subways to Solve Congestion, Climate, and Land Use Crises

This independence from surface chaos ensures an unmatched capacity for passenger movement. A modern metro line can move upwards of 40,000 passengers per hour per direction (PPHPD). No other mode—not buses, streetcars, or even multi-lane highways—can move people in such volume within a constrained urban corridor. In a mega-city like Tokyo, London, or New York, the metro is the only system capable of sustaining the daily gravitational pull of the central business district.