Donald Trump on Wednesday ordered the reopening of a review of future fuel economy and emissions standards for US cars, in a move that could slow down development of electric vehicles and new efficiency technologies. Regulations confirming standards for vehicle emissions in 2022-25, which were hurried through in the final fortnight of Barack Obama’s administration, will instead be reviewed next year. The Obama administration estimated that the rules would cost car manufacturers in the US $33bn. The new administration’s move, which had been sought by the large car manufacturers, coincided with a visit by the president to Michigan to meet industry executives and workers. Addressing autoworkers bussed to a disused factory outside Detroit which the President said had been used during the second world war to build B-24 bombers, Mr Trump promised to “make Detroit the car capital of the world again” adding: “we are going to restore the originally scheduled midterm review and ensure that any regulations we have protect your jobs.” Jessica Caldwell, analyst at Edmunds, said the emissions targets had forced manufacturers to shift research and development budgets from the trucks and SUVs consumers most wanted towards electric vehicles and hybrids, whose sales are shrinking. “Trump is likely scoring points with the auto executives by promising to rethink these regulations, but he’s making it clear he expects the automakers to return the favor by ramping up investments here in the US,” she said.