According to a 2016 study conducted by the U.S. Environmental Protection Agency (EPA), transportation accounts for 28% of total greenhouse gas emissions in the U.S.  The transportation economic sector includes the movement of people and goods by cars, trucks, trains, ships, airplanes, and other vehicles, however, the largest sources of transportation-related greenhouse gas emissions include passenger cars and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans.  These sources account for over half of the emissions from the transportation sector. The remaining greenhouse gas emissions from the transportation sector come from other modes of transportation, including freight trucks, commercial aircraft, ships, boats, and trains, as well as pipelines and lubricants.  The majority of greenhouse gas emissions from transportation are carbon dioxide emissions resulting from the combustion of petroleum-based products, like gasoline, in internal combustion engines.

Based on 2014 data from an EPA study, U.S. greenhouse gas emissions totaled 6,870 million metric tons of carbon dioxide equivalents. This total represents a 7 percent increase since 1990 but a 7 percent decrease since 2005.  So how can we keep this number decreasing as it has been since 2005?  By implementing regulations and restrictions for fossil fuel consumption and combustion, but also by introducing alternative methods of transportation and best practice methods for transportation.  An example of a regulation is the EPA’s light-duty vehicle greenhouse gas rules, which are projected to save consumers $1.7 trillion at the pump by 2025, and eliminate 6 billion metric tons of greenhouse gas pollution. An example of a best practice method would be to reduce the travel demand by employing urban planning to reduce the number of miles that people drive each day and reducing the need for driving through travel efficiency measures such as commuter, biking, and pedestrian programs such as the EPA’s Smart Growth Program. As a country the U.S. can learn from practices other countries have implemented such as Germany, who is testing out a trial run of offering free public transportation in an effort to reduce greenhouse gas emission. The EPA on behalf of the U.S. is trying, but are we trying hard enough?