The transportation sector became the largest source of U.S. greenhouse gas (GHG) emissions in 2016. Driven by increased travel demand, low fuel prices, and urban sprawl, transportation emissions grew about 23 percent between 1990 to 2019. To change this trajectory, states have utilized several types of alternative vehicle policies including vehicle GHG emissions standards, zero-emission vehicle (ZEV) mandates, and financial incentives for purchasing alternative vehicles and building alternative vehicle infrastructure. These policies incentivize the increased use of several types of alternative fuel vehicles including battery-electric vehicles (BEVs), plug-in hybrid-electric vehicles (PHEVs), and hydrogen fuel-cell vehicles (FCEVs).

Regarding vehicle emissions and fuel economy standards, the federal government sets standards in the United States to avoid having many different state standards which could put a significant regulatory burden on vehicle manufacturers. Greenhouse gas emissions are regulated by the Environmental Protection Agency (EPA), and fuel economy standards are regulated by the National Highway Traffic Safety Administration (NHTSA), often—but not necessarily—in a joint rulemaking. California has unique authority through a waiver under Section 209 of the Clean Air Act to maintain motor vehicle emissions standards that are stricter than the federal standards.

California’s motor vehicle emission standards are referred to as the Low-Emission Vehicle (LEV) standards, which are part of the state’s larger Advanced Clean Cars Program. The LEV III standards, which govern new passenger vehicles through model year 2025, set increasingly stringent emissions standards for criteria pollutants and greenhouse gases. In addition to these standards, California has its  Zero Emission Vehicles (ZEV) program, which is also part of the Advanced Clean Cars Program. The ZEV program, which applies only to light- and medium-duty vehicles, requires manufacturers to produce and deliver for sale an increasing number of low-emitting and zero-emitting vehicles, growing from 4.5 percent in model year 2018 to 22 percent in model year 2025. The program awards “ZEV credits” to manufacturers for each qualifying vehicle they deliver for sale based on the vehicle’s all-electric range. Manufacturers must acquire a specific number of ZEV credits depending on their size.

California also has an Advanced Clean Trucks Program, which requires manufacturers producing Class 2b–8 vehicles in California to sell zero-emission trucks as an increasing percentage of their sales from 2024 to 2035.

Under Section 177 of the Clean Air Act, other states may adopt California’s Advanced Clean Cars standards, including one or both of its LEV standards and ZEV regulation, but they may not develop independent standards. As of August 2022, fourteen states have adopted both California’s ZEV program as well as the LEV standards: Colorado, Connecticut, Maine, Maryland, Massachusetts, Minnesota, New Jersey, Nevada, New Mexico, New York, Oregon, Rhode Island, Vermont, Virginia, and Washington. Delaware, Pennsylvania, and the District of Columbia are following California’s LEV standards but have not adopted the ZEV program. Together, all 17 of these states and the District of Columbia are referred to as “Section 177 states.”

California, Connecticut, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island, and Vermont are also part of the Multi-State ZEV Task Force, which was established in 2013 to coordinate the implementation of policies and programs to increase the deployment of electric vehicles in their respective states. The Task Force set a target to cumulatively have 3.3 million ZEVs operating in their jurisdictions by 2025. In 2020, Colorado, the District of Columbia, Hawaii, Maine, North Carolina, Pennsylvania, and Washington joined the ZEV Task Force states in signing a multi-state memorandum of understanding focused on zero-emission medium- and heavy-duty vehicles, and in 2022 the ZEV Task Force released the Multi-State Medium- and Heavy Duty Zero-Emission Vehicle Action Plan laying out strategies to reach its goal of making 100 percent of new sales of medium- and heavy-duty vehicles in their jurisdictions ZEVs by no later than 2050, with 30 percent of sales zero-emission by 2030.

In 2017, Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming signed a memorandum of understanding to create the Regional Electric Vehicle Plan for the West (REV West) to promote a “seamless” EV charging network across the region’s major transportation corridors.

In 2021, Illinois, Indiana, Michigan, Minnesota, and Wisconsin signed a memorandum of understanding to create the Regional Electric Vehicle Midwest Coalition (REV Midwest) with the goals of accelerating medium- and heavy-duty fleet electrification, elevating economic growth and industry leadership, and advancing equity and a clean environment.

Last updated August 2022.