If President Trump gets his way, California will no longer be able to force automakers to achieve specific fuel economy mandates that aren't inline with federal rules.
The state's ability to set its own rules has also let to regulations that many in the trucking industry have found onerous.
Carper said a leaked earlier draft showed that under the proposal, US vehicles would use 206 billion gallons of gasoline more than expected from 2020 to 2050 if the standards remained unchanged. Obama's plan would have required automakers to build cars that are increasingly more fuel efficient every few years until 2025. It also intends to revoke California's authority to regulate its own automobile emissions, sparking what will likely be a lengthy court battle.
"Congress didn't intend for California to set national fuel economy standards", said Steve Milloy, a policy adviser for the Heartland Institute, a group critical of climate science. The EPA and the federal transportation department will unveil a proposed legislation for the state, which will then be open for debate, before the agency makes a decision.
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The administration also contends the new rule would reduce "societal costs" by about $500 billion over the life of the vehicles but the administration's overall forecast net benefits are unclear, once higher fuel consumption is taken into account.
The proposal is still in the final stages of a broad interagency review led by President Donald Trump's Office of Management and Budget, but these major elements of the plan were not expected to change, the people said.
In addition, the Trump administration plans to propose a rule that would revoke a waiver California was granted by the EPA under the Clean Air Act, which allowed California to set its own emissions rules and requirements for zero emission vehicles.
In its legal analysis, Holmstead said, EPA could determine that California did not face "compelling extraordinary conditions", compared to other states, in needing to reduce greenhouse gases, such as carbon dioxide. In March 2017, former Environmental Protection Agency administrator Scott Pruitt was reportedly looking at ways to remove California's waiver, according to a report from The New York Times.
Representative Jimmy Gomez, a California Democrat, wrote on Twitter that the state's "vehicle emissions standards are a big part of our environmental identity". NHTSA is planning to argue that a 1975 law that enacted the first federal fuel efficiency standards prohibits the state from regulating tailpipe emissions. "National fuel economy standards are set by the federal government so that's what we are going to do". Meanwhile, California has announced that the state plans to take legal action to fight the intrusion into their state politics. So California's standards are now in sync with the federal government's.