His lawyers also adopted the broad position that the president is immune from being subjected to a criminal probe while in office, and the US Constitution requires Vance to wait until after Trump leaves the White House.
State officials, however, disagree with the decision.
Trump sued to block NY prosecutors from their push to obtain his returns as part of a criminal investigation into payments made to two women who claimed to have affairs with Trump.
The move "exceeds NHTSA's authority, contravenes Congressional intent, and is arbitrary and capricious, and because NHTSA has failed to conduct the analysis required under the National Environmental Policy Act", states the complaint filed in the U.S. District Court for the District of Columbia.
The law was seen as a swipe against Trump, who has resisted releasing his tax returns. "Yet, the administration insists on attacking the authority of California and other states to tackle air pollution and protect public health", said Xavier Becerra, the California attorney general, in a statement. As a practical matter, building lighter cars with better mileage is the most effective way of curbing greenhouse gas emissions; the California plan would hike average mileage from about 35 mpg to 50 mpg. "27, was unconstitutional on a number of different grounds and he issued an injunction that means this law will not go into effect", she said. Dhillon said that no presidential candidate will be required to release their taxes as a condition of being on the ballot.
The U.S. Transportation Department did not immediately comment on the suit.
"In addition, the Federal government itself adopted emissions standards that would reduce greenhouse gas emissions, and also chose to raise fuel efficiency to over 50 miles per gallon by 2026", Rosenblum's office said, referencing an Obama-era decision.
"We're in a unusual place", said Jack Lienke, regulatory policy director for New York University School of Law's Institute for Policy Integrity. Here's the ironic part of California's emission laws: California is not only in the top 10 of the most polluted USA cities by ozone, it holds 8 of the 10 spots according to the American Lung Association with its current emissions laws.
The law was signed by Gov. Gavin Newsom in July.
Brown argued it would create a slippery slope that could lead states to impose requirements like medical records or college transcripts.
Roque de la Fuente, who filed one of the lawsuits and was a minor-party presidential candidate in 2016 after failing to win support in the Democratic Party, said he supports some limited, voluntary tax return disclosure. "But it does have implications that are far reaching".
The California measure requires presidential candidates to release five years of tax returns in order to appear on a nominating ballot in California, the most populous US state.
Trump is separately trying to block Deutsche Bank AG (DBKGn.DE) from handing over financial records, which the bank has said include tax returns, sought by the House committees.
According to the new lawsuit, Trump's attorneys attempted to negotiate with Vance and he refused to narrow the subpoena.