No new date was given, but Lynda Tran, a spokeswoman for the U.S. National Highway Traffic Safety Administration, told Bloomberg that, "The rule is still undergoing interagency review and we expect that process to be completed soon."
The administration has said the new efficiency requirements, which should result in real-world EPA figures of around 40 mpg, will save drivers money and have been upheld in court. Still, the rules have attracted the ire of some of the President's opponents. Without further clarification from Washington, we can't be sure what the hold up is. Anyone want to speculate?