The Department of Transportation advanced a new interpretation of the country’s fuel economy law that paves the way for a weakening standard for heavy-duty trucks.

In a new “interpretive rule” announced late last month, the Trump Administration claimed the Energy Independence and Security Act of 2007 only allows the National Highway Traffic Safety Administration, an agency within the Transportation Department, to regulate the fuel efficiency of entire vehicles. The new interpretation claims the agency has no authority to regulate “standalone engines or vehicle subcomponents.”

The interpretation applies to heavy duty vehicles, such as 18-wheelers and dump trucks.

An Aug. 28 press release states that the new interpretation is about “returning that authority to vehicle manufacturers who can best decide how to improve fuel efficiency.”

“American innovators – not Big Government – know how best to design vehicle engines,” the agency’s director, Jonathan Morrison, said in the statement.

The move does not immediately change fuel economy standards for medium and heavy duty vehicles but makes it easier for the administration to later lower these standards, according to E&E News.