Volume 17, Issue 2, 2025
Authors: I-Shian Suen
The Impact of Public Transportation on the Reduction of Greenhouse Gas Emissions in the United States
Greenhouse gases (GHGs) contribute to global warming and climate change by trapping heat in the Earth’s atmosphere. The U.S. Environmental Protection Agency (EPA) states that transportation accounted for 28.4% of the total GHG emissions in 2022, making it a significant contributor. Decreasing personal vehicle travels can help reduce GHG emissions, and using public transportation is a viable way to achieve it. This study evaluates the impact of public transportation on reducing GHG emissions in the U.S. and it included 292 urban areas with public transportation services, divided into two groups, based on whether the metropolitan population is over or under one million. The analysis considered data on: GHG emissions, with a 0.1° by 0.1° resolution; public transportation usage (passenger miles travelled); and on workers commuting to work using private vehicles. The findings from the regression analysis indicated that: (1) public transportation usage reduces GHG emissions, although the effect is minimal; (2) commuting to work using private vehicles increases GHG emissions, which has a greater impact than public transportation usage; and (3) both factors explain more variance in GHG emissions in urban areas with populations over one million compared to those with populations under one million. These findings align with the existing literature, demonstrating that public transportation usage can decrease GHG emissions by 0.77% in urban areas with populations over one million, and by 1.03% in those with populations under one million.
https://doi.org/10.37043/JURA.2025.17.2.4
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