Administration eases fuel rules for heavy-duty trucks

The Transportation Department issued a new legal interpretation asserting it lacks authority to set separate engine efficiency standards for medium and heavy trucks, effectively pausing enforcement of Obama-era requirements. Officials said the move gives manufacturers flexibility in meeting overall fuel efficiency targets. Environmental advocates warned that weaker standards could raise fuel costs for truckers and consumers.

The new interpretation specifically targets the engine component of the Obama-era efficiency framework, which had established separate requirements for both complete vehicles and their powertrains. While the existing engine standards remain on the books, the department signaled it will suspend enforcement while it drafts a formal rule to codify the change. NHTSA's Jonathan Morrison framed the shift as empowering manufacturers to determine their own engineering approaches rather than following federal mandates.

This action continues a broader pattern of the administration rolling back vehicle regulations tied to fuel economy, climate, and emissions. Environmental groups such as the Sierra Club argue that reduced efficiency for commercial trucks will deepen diesel dependence and expose truckers and businesses to volatile fuel prices, with those costs ultimately reaching consumers.