The transportation sector became the largest source of U.S. greenhouse gas emissions in 2016. While transportation sector emissions have fallen by 6.1 percent from their 2005 peak, transportation sector emissions grew about 21.5 percent from 1990 to 2016, largely driven by increased demand for travel based on economic and population growth, low fuel prices, and urban sprawl. To change this trajectory, the states shown on this map have enacted vehicle GHG emissions standards, adopted goals for zero-emission vehicle (ZEV) deployment, which include both plug-in electric vehicles (EVs) and fuel cell electric vehicles (FCEVs), and provided rebates for ZEVs and incentives for ZEV infrastructure, such as EV supply equipment (EVSE) and hydrogen fueling infrastructure.
On vehicle emission standards, California has unique authority under Section 209 of the Clean Air Act to maintain motor vehicle emission standards that are stricter than the federal standards, as long as the federal government has issued a waiver. California refers to its motor vehicle emission standards as the Low-Emission Vehicle (LEV) standards. Moreover, as part of its larger Advanced Clean Cars Program, California’s Zero Emission Vehicles (ZEV) program requires major manufacturers of passenger cars and light trucks (up to 8,500 pounds) to attain a certain number of ZEV credits depending on the number of vehicles produced and delivered for sale in the state. ZEVs include plug-in electric vehicles and hydrogen fuel cell electric vehicles.
Other states may adopt California’s standards under Section 177 of the Clean Air Act, but they may not develop independent standards. As of December 2018, nine states have adopted both California’s ZEV program as well as the LEV standards: Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island, and Vermont. These nine “ZEV states” are following California’s lead in requiring automakers to produce ZEVs to improve local air quality and reduce the emissions contributing to climate change. Four other states—Colorado, Delaware, Pennsylvania, and Washington – and the District of Columbia are following California’s LEV standards, but have not adopted the ZEV program. Together, all 13 of these states are referred to as “Section 177 states.”
Please also see the C2ES map outlining U.S. Low Carbon Fuel Standards and Alternative Fuel Standards to review additional policies to reduce GHG emissions from the transportation sector.
Last Updated January 2019