Now, automakers will have more time to fight the standards, as the review process could take about a year. The review, Trump said, will "ensure that any regulations we have protect and defend your jobs", but the changes coming from robot automation are likely to have a bigger impact than fuel economy rules.
Supporters of the emissions standards have warned the Trump administration against undoing the rules.
The Trump administration will "spend another year looking at the data in front of us", a senior White House official told reporters on a conference call Tuesday.
Automakers have agreed that cheap gas and the rise in popularity of utility vehicles will make the current standards almost impossible to achieve.
The backdrop and message underscored Mr Trump's efforts to lock down support in industrial states such as MI that put him in the White House. They would bring fleetwide fuel efficiency to a projected 50.8 mpg in 2025.
But rolling back the standards, said Sierra Club executive director Michael Brune, risks "endangering the health of our children and families by abolishing life-saving vehicle emissions protections that cut down on unsafe smog pollution and asthma attacks". That agreement will start to unravel Wednesday with Trump's action, which will direct the EPA to re-open the rule-making for the mileage standards.
The standards stemmed from a 2012 deal between the Obama administration and the industry that combined in a single set of regulations the rules on vehicle emissions, the Corporate Average Fuel Economy or "Café" standards, and California's state requirements.
The nuclear option. Trump could kill waivers that now allow California to set its own mileage and emissions standards, a regime that dates to 1970, when the federal Clean Air Act was enacted.
If Trump wants to protect auto industry jobs, he should look at robot automation instead.
California and a some states have adopted more stringent clean vehicle rules than the federal government. We are going to be fair.
"These standards are costly for automakers and the American people", said EPA Administrator Scott Pruitt, in a statement.
"What we see is that where the use of robots are on the rise, unemployment is falling", Jeff Burnstein, president of A3 that holds a robot automation trade show, told Inverse in an interview in January.
"Fuel economy standards support innovation, keep our air clean and save money at the pump - all things Canadians want", Workman said.
NY is joined by a handful of other states - including Maine, Maryland, Massachusetts, Oregon, Rhode Island, Vermont, and Washington - in opposing the Trump administration's rollback of these standards.
Democratic Senator Edward Markey of MA said Trump's move will lead to needless uncertainty for the auto industry.