Reduced / Sequestered
Curitiba, Brazil, developed the first bus rapid transit (BRT) system in the 1970s, a model replicated in more than 200 cities worldwide. Dedicated BRT lanes along main thoroughfares—separate corridors from automobiles—were installed for 50 times less than the cost of rail. Bus stops were designed to be more like metro stations with multiple points of entry and exit.
All mass transit modes use scale to their emissions advantage. When someone opts to ride a streetcar, bus, or subway rather than driving a car or hailing a cab, greenhouse gases are averted.
The benefits go beyond emissions reduction and accrue to all city dwellers, not just those who use mass transit. By reducing the volume of cars, mass transit relieves traffic congestion. With fewer people driving, fewer accidents and fatalities take place. Overall, air pollution drops. Mass transit also makes cities more equitable by providing mobility to those who cannot drive.
Urban transport is the single largest source of transportation-related emissions, and growing. With good urban design, mass transit can help embed mobility, livability, and sustainability in cities.
Use of public transit is projected to decline significantly from 30 percent of urban travel as the low-income world gains wealth. If use is instead managed to decline more slowly by 2050 or even rise slightly to 35 percent, this solution can save 7.5–23 gigatons of carbon dioxide emissions from cars. Consumers would save US$2.1–6.6 trillion in mobility costs. Our analysis includes diverse public transit options (bus, metro, tram,and commuter rail) and examines the costs that travelers pay (car purchase and use compared to buying transit tickets).