“California has been a driver of innovation, including in the automobile pollution space, since the 1960s, and this new directive will continue that tradition,” says Stanford University environmental law professor Deborah Sivas in an email to Popular Science. “It is likely that a dozen or more other states will follow suit, as they are currently permitted to do under the Clean Air Act, potentially affecting more than one third of the new car market.”

“Even if California’s ambitious goal is not strictly met,” Sivas adds, “it has the near-term benefit of increasing regulatory certainty for the automobile and aligned industries that will drive the necessary transition to non-fossil fuel transportation. And that increasing certainty creates powerful incentives for innovation.”