Expanding public transportation and infrastructure that promotes walking and biking throughout the world’s cities could save $100 trillion and cut transportation-related carbon emissions by 40 percent by 2050, according to an analysis by researchers at the University of California, Davis, and the Institute for Transportation and Development Policy.

Urban transportation accounted for roughly one-quarter of all transportation-related emissions in 2010, the report said, and these emissions could double by 2050 as growth continues in major cities in China, India, and other developing countries.

CO2_emissions-600This chart compares projected urban transportation-related emissions in 2050 under two scenarios: “business as usual,” shown in red, and the “high shift” scenario, shown in green. Under the “high shift” scenario, countries make major improvements in urban mass transit and infrastructure that promotes walking and biking. Transportation-related emissions from 2010, in black, are shown for comparison. (Image source: UC-Davis, ITDP)

If China alone were to develop extensive bus rapid transit and commuter transit networks, its predicted transportation-related emissions in 2050 could be cut by 40 percent, the analysis found.

The U.S. — currently the world’s largest contributor to urban transportation-related emissions — is seeing declines in that sector as population growth slows, vehicle fuel efficiency improves, and people drive less. But those emissions cuts could accelerate sharply, to half the levels currently predicted for 2050, if urban mass transit were improved.

Redirecting funds from road construction, parking garages, and other infrastructure elements that encourage car ownership to public transportation would save trillions in public and private dollars, the analysis found.


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