The U.S. Environmental Protection Agency Administrator reaffirmed the Trump administrations claim that it would not cooperate with California on establishing fuel economy rules.

EPA Administrator Andrew Wheeler said the president's administration would roll back fuel economy rules that are designed to reduce greenhouse gas emissions, according to The Detroit News. The stringent emission rules that were implemented during the Obama administration would require automakers to produce fleets that average more than 50 miles per gallon by 2025.

In February, the U.S. government ended negotiations with California on the rollback of fuel economy rules, according to Reuters. The Trump administration also made a proposal in August 2018  to freeze fuel efficiency standards after 2020 and strip California, and states with similar goals, of the ability to impose stricter rules.

Trump administration officials representing the EPA and NHTSA held a "tense" late-February conference call with auto manufacturing executives on the topic of fuel economy standards giving them an ultimatum: support President Donald Trump’s plan to ease Obama-era regulations or side with California, which sets its own, stricter standards.