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

What it does

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.

The National Highway Traffic Safety Administration's summary, as published in the Federal Register.

What changed in the regulation

3 parts of Title 49 of the Code of Federal Regulations:

49 CFR 523, 49 CFR 534, 49 CFR 535

Compared with

The National Highway Traffic Safety Administration has published 23 final rules in 2026 so far, compared with 10 in all of 2025.

Counted by the Tribune from Federal Register records since Jan. 1, 2025.

What happens next and when

This interpretive rule is applicable as of August 31, 2026.

The agency's dates, word for word.

Check it yourself

• The document in the Federal Register
• Docket NHTSA-2026-1948 on Regulations.gov
• Title 49 on eCFR

The record as published

Source: the Federal Register (public domain). The document in the Federal Register