DETROIT (Reuters) - The Trump administration’s chief environmental regulator said on Tuesday final U.S. vehicle carbon dioxide standards due out later this year could be more restrictive than current rules enacted by the Obama administration because they will eliminate certain loopholes.

FILE PHOTO: U.S. Environmental Protection Agency (EPA) Administrator Andrew Wheeler testifies before a House Energy and Commerce Environment and Climate Change Subcommittee hearing on the FY2020 EPA Budget on Capitol Hill in Washington, U.S., April 9, 2019. REUTERS/Yuri Gripas/File Photo

“In some of the out years, we’re actually more restrictive on CO2 emissions than the Obama proposal was” because the proposed Trump administration rules will eliminate “off ramps” that make it easier for automakers to comply, Environmental Protection Agency Administrator Andrew Wheeler told reporters after a speech to the Detroit Economic Club.

Wheeler said the final proposal will not be look “exactly like” the original one announced in August 2018 to freeze fuel efficiency standards at 2020 levels through 2026. He declined to offer more details.

Work is continuing on revisions to the vehicle efficiency and emissions standards, which are overseen by EPA and the Department of Transportation, he said.

On a separate point, Wheeler said the EPA is prepared to enact new regulations to curtail smog, and plans to set new standards next year for nitrogen oxide emissions from heavy trucks.

The Trump administration is embroiled in a legal battle over automotive tailpipe emissions with the State of California and other states that want to keep Obama administration standards, which call for pushing the average fuel efficiency of new vehicles to 46.7 miles per gallon by 2026.

The Trump administration’s earlier proposal called for freezing the average vehicle fuel efficiency target at 37 mpg. Wheeler said he is hopeful California regulators will have a different view when they see the administration’s final proposal.

Only three automakers complied with U.S. fuel efficiency standards in 2017, Wheeler noted, saying the Obama rules “are not based on reality.”

Wheeler used the speech to the Detroit Economic Club to defend the administration’s environmental record. The decision to scrap the Obama fuel economy targets and strip California of its authority to set its own standards for vehicle CO2 emissions are aimed at making new vehicles less expensive, and encourage consumers to buy newer, safer vehicles, Wheeler said.

Automakers are pushing ahead with plans to invest billions in new electric vehicles. General Motors Co, for example, has proposed spending $3 billion to convert a Detroit assembly plant to build electric trucks and vans.

Five automakers, Ford Motor Co, Honda Motor Co, BMW AG, Volkswagen AG VOWG_p.DE and Daimler AG DAIGn.DE>, voluntarily agreed with California to adopt the state's emissions standards.

Wheeler was critical of electric vehicles and electric vehicle subsidies. He told the Detroit audience regulations that effectively mandate electric vehicle sales will result in automakers raising prices for sport utility vehicles and trucks so they can sell electric cars at lower prices.

California should focus on limiting smog-forming pollutants, and still has the power to do so, Wheeler said.

“California has the worst air quality in the Untied States,” Wheeler said. “We hope the state will focus on these issues ... rather than trying to set fuel economy standards for the nation.”