Transport makes up the majority of emissions in the U.S. Transportation includes cars, trucks, trains, planes and boats, where the road transportation is the main constituent in transportation emissions, especially cars. In comparison to parts of the western world, the U.S. relies heavily on motorized transit rather than other modes of transport such as bicycling or walking. Additionally, the majority of U.S. citizens commute to work using private vehicles.
Transport emissions include not only carbon dioxide, but also nitrous oxide, nitrogen oxide, methane, hydrofluorocarbons (HFCs), perfluorocarbon (PFCs), and sulfur hexafluoride (SF6). These greenhouse gases are significant contributors to climate change which has led to extreme temperatures, rising sea levels and an increase in ocean temperature, increase in heavy precipitation and shrinking glaciers. Climate change threatens global ecosystems including animal and human life. The U.S. have established several regulations and agreements for environmental protection however, President Donald Trump decided in 2017 that the United States would cease all participation from the 2015 Paris Agreement. In order for the U.S. to lower transportation emissions, enhancing or subsidizing transport electrification and energy efficiency is essential for making the transportation industry more environmentally conscious.