Final rule · 2026-17756

Resetting NHTSA's Fuel Economy Program: Commercial Medium- and Heavy-Duty On-Highway Vehicles and Work Trucks

The National Highway Traffic Safety Administration is issuing this interpretive rule regarding the scope of its authority to set fuel economy standards for commercial medium- and heavy-duty on-highway vehicles and work trucks. This rule describes NHTSA's authority to set vehicle standards, which does not include the authority to set separate standards for engines. NHTSA will review its existing standards applicable to commercial medium- and heavy-duty on-highway vehicles and work trucks for consistency with this interpretation in a separate rulemaking. Pending the rulemaking process, NHTSA will exercise its enforcement authority with regard to affected standards in accordance with the interpretation set forth in this rule.