NHTSA Moves to Scrap Truck Fuel Economy Standards

The National Highway Traffic Safety Administration is moving to narrow its authority over fuel-efficiency standards for standalone medium- and heavy-duty truck engines, reversing an Obama-era policy that extended federal oversight beyond complete vehicles. The Truck and Engine Manufacturers Association welcomed the review, while existing fuel-efficiency requirements remain in place during the rulemaking process.

NHTSA Reconsiders Engine-Only Authority

NHTSA has issued an interpretive rule stating that the agency cannot regulate medium- and heavy-duty truck engines independently from the vehicles in which they are installed. The action reverses a prior interpretation that allowed the agency to establish efficiency requirements for standalone commercial truck engines.

The agency’s position is that its statutory authority applies to complete on-road vehicles, rather than engines treated as separate products. NHTSA is expected to address the issue through a broader rulemaking covering fuel-efficiency requirements for medium- and heavy-duty vehicles and work trucks.

Existing standards remain in effect while the agency reviews the regulatory framework. The potential change could affect how future efficiency requirements are developed, certified and enforced for commercial vehicles.

Manufacturers Seek Flexibility

EMA said it supports a review of the standards and plans to work with NHTSA as the agency develops a final rule.

“EMA looks forward to working with NHTSA as the agency develops a final rule addressing fuel efficiency standards for medium- and heavy-duty vehicles that reflect real-world customer adoption of fuel-saving technologies, deliver meaningful operational and economic benefits to customers, and provide manufacturers the flexibility to develop engines and vehicles that meet the diverse demands of the commercial vehicle market,” the association said.

For truck manufacturers, the issue involves how fuel-saving technologies are evaluated across different vehicle types and applications. Regional-haul tractors, long-haul trucks, vocational vehicles and other commercial equipment operate under substantially different conditions, including variations in payload, duty cycle and fuel use.

Potential Effects on Truck Costs and Fuel Use

Earlier federal estimates for the broader Phase 2 heavy-duty vehicle program projected approximately $170 billion in lifetime fuel savings for truck owners and a reduction of about 1.1 billion metric tons of carbon dioxide emissions from covered vehicles.

Those estimates were based on standards covering vehicles and engines under the existing regulatory approach. Changes to the scope or structure of future requirements could affect vehicle development costs, available powertrain technologies and expected fuel savings for fleets.

NHTSA has also proposed changes to fuel-economy requirements for passenger cars and light trucks, including lower fleetwide targets for model years 2022 through 2031. The agency estimated that proposal could reduce the average cost of a new vehicle by about $930, but those estimates do not directly determine the effects of the separate medium- and heavy-duty truck review.

Final Rule Still Pending

NHTSA’s interpretive action does not by itself establish a new set of truck fuel-efficiency standards. The agency must complete its rulemaking before any revised requirements or enforcement structure take effect.

The final outcome will determine whether future commercial truck efficiency standards are written primarily around complete vehicles, engines, or a combination of both. Manufacturers, fleets and other industry stakeholders are expected to monitor the process for details on compliance requirements and implementation timelines.