As automakers await the National Highway Traffic Safety Administration's new fuel-economy rules for 2022 through 2025, due March 30, regulators from California and Washington are still hammering out the specifics.

A meeting between state and federal regulators on fuel-economy and emissions targets took place on Monday as both sides attempt to avoid a prolonged and costly legal battle that could put the final regulations into limbo for months or years.

The current targets see automakers aiming for an average EPA window-sticker rating of roughly 38 mpg across all vehicles by 2025, but the Trump administration has said it intends to freeze or even roll back that target.

READ MORE: CAFE proposal coming March 30: automakers hope national rules survive

The sitdown between officials from the California Air Resources Board and federal regulators from the NHTSA and Environmental Protection Agency was held at a coffee shop close to the White House, according to a report Wednesday in The Wall Street Journal.

At that meeting, federal officials asked their California counterparts if the state would be willing to relax future its fuel-economy and carbon-emission goals.

California is allowed to set its own emission limits, separate from national rules issued by the EPA, under more than 40 years of precedent established in the courts.

Chrome exhaust pipe

Chrome exhaust pipe

California has operated for decades under what's commonly called "the California waiver," given to the state by the EPA, that lets the state regulate its own air quality—as it did even before the EPA was established in 1970.

Twelve other states piggyback on California's clean-air rules, and the states that have adopted those limits represent about 40 percent of the U.S. population.

California's officials were said to be noncommittal about relaxing their rules, but vowed to continue discussions with Washington.

READ MORE: Trump EPA backs away from attacking California emission waiver

Automakers greatly fear two different regulatory regimes, which could require them to track sales and emissions separately in the two groups of states, and possibly limit the vehicles or volumes they can sell in the stricter states.

The Trump administration was thought to have considered revoking that waiver last year, but EPA head Scott Pruitt later told reporters the waiver wasn't under review.

The request from national regulators to California that it consider relaxing its emission limits is only the latest in a long list of actions by the Trump administration in which climate-science deniers have cut, rolled back, or ignored efforts to cut carbon emissions under the guise of reducing regulation.

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