"WASHINGTON - A U.S. appeals court on Friday tossed out greenhouse gas emissions rules for heavy-duty truck trailers, ruling two government agencies had exceeded their authority.

The Environmental Protection Agency (EPA) and National Highway Traffic Safety Administration (NHTSA) in 2016 set rules for the first time requiring trailer manufacturers to adopt fuel-saving technologies like side skirts and automatic tire pressure systems. An industry group challenged the rule, which was put on hold by the court pending the review.

The administration of then-President Barack Obama said it was important to regulate the fuel efficiency of the trailer portion of commercial tractor-trailers "because large tractor-trailers account for 60% of the fuel consumption and carbon dioxide emissions from heavy-duty vehicles.""

David Shepardson and Sebastien Malo report for Reuters November 12, 2021. [2]