Heavy-duty engines and vehicles will be subject to more stringent environmental standards starting in model year 2027 under a final rule signed by U.S. Environmental Protection Agency Administrator Michael Regan Dec. 20. The rule sets a new standard to cut smog- and soot-forming emissions from heavy duty vehicles by 50% over current levels by 2045.
The rule covers nitrogen oxide (NOx) emission from heavy duty gasoline and diesel engines. It is primarily targets on-highway vehicles, but it includes provisions covering engine categories like off-highway spark-ignition engines and compression-ignition engines that are used in some construction equipment. Regan called the new requirements “strongest-ever national standards” for the vehicle types covered by the rule.