Colorado has become the 11th state to adopt California's zero-emission-vehicle mandate forcing automakers to sell more electric cars in the state.
The new rule was passed by Colorado's air-quality commission by a vote of 8 to 1 on Aug. 23. It requires at least 5% of an automaker's new car lineup to be electric vehicles, or EVs, by 2023 and more than 6% by 2025.
"It's a modest proposal in the face of a critical threat. Where the federal government refuses to act, states must lead," Garry Kaufman, director of Colorado's Air Pollution Control Division, said in a statement.
The Colorado agreement, which echoes the one announced by California regulators, is tougher than the planned rollback of the Corporate Average Fuel Economy, or CAFE, standards the White House previously outlined.
Similar to California's zero-emission vehicle rules, automakers are granted some flexibility by receiving credits for the electric cars they sell before the new mandate is put into place. Companies can also buy credits from other automakers that outperform emissions targets.
The credit value of electric vehicles will depend on the vehicle's zero-emission range.
Colorado already has one of the highest rates of EV sales in the nation at 2.6% last year — twice the national average.
Under the state's new rules, automakers can include both plug-in hybrids and fully electric vehicles to meet the sales requirement. People shopping for a new car are not required to buy an EV or plug-in hybrid.
The state's new governor Jared Polis, has made environmental protection a cornerstone of his administration.
The funding for that came from the $68 million Colorado was awarded as part of the Volkswagen Dieselgate settlement and will help make the state's fleet electric, and switch to battery-electric transit buses.
By adopting the California regulations, Colorado also sets itself up to clash with President Donald Trump over his push to roll back emissions and fuel economy standards.
The other states that have adopted California's electric vehicle mandate include: Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island and Vermont.