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

Environmentally, the benefits are profound. Every time a person chooses the metro over a solo car trip, there is a significant reduction in greenhouse gas (GHG) emissions and air pollutants like nitrogen oxides and particulate matter. Metros are energy-efficient per passenger-mile, and as more urban power grids adopt renewable energy, the transit system becomes an increasingly cleaner mode of mass movement.