19. Department of Transportation · Notable

Restore DOT primacy over fuel economy standards against EPA CO2 rules

Done

Printed page 628 19. Department of Transportation

“Ensure that DOT again exercises priority in the setting of fuel economy standards. Any EPA limits on carbon dioxide emissions, even if authorized under the Clean Air Act, must support and work in harmony with DOT standards and must not override them or usurp DOT’s regulatory role under EPCA.”

What has happened

Feb 18, 2026 Done
EPA finalized the rescission, repealing all greenhouse gas emission standards for light-, medium- and heavy-duty vehicles and engines and holding that CAA section 202(a)(1) does not authorize them. There is now no EPA carbon dioxide limit on new motor vehicles to override or duplicate NHTSA's standards, which leaves DOT the sole federal setter of vehicle efficiency requirements under EPCA — the priority the Quote asks for. NHTSA had already reasserted the statutory limits on its own CAFE authority in an interpretive rule of 2025-06-11 and proposed the SAFE Vehicles Rule III on 2025-12-05.
- EPA final rule: Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air Act
  Primary Executive branch Feb 18, 2026
- NHTSA interpretive rule: Resetting the Corporate Average Fuel Economy Program
  Primary Executive branch Jun 11, 2025
Aug 1, 2025 Attempted
EPA proposed to rescind the 2009 endangerment finding and, with it, every greenhouse gas emission standard for light-, medium- and heavy-duty vehicles — the Clean Air Act rules that had been setting a de facto second fuel-economy standard alongside NHTSA's. The proposal changed nothing by itself; a public hearing was noticed the same day and the comment period extended on 2025-08-15.
- EPA proposed rule: Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards
  Primary Executive branch Aug 1, 2025

Research log

What was searched, and what didn’t count as evidence

Research notes

Boundary call, flagged in .scratch/research-phase/spot-checks.md. done on the reading that the ask is about primacy: with EPA’s vehicle GHG standards repealed there is nothing left to override DOT’s EPCA role. The alternative is partial — NHTSA’s own replacement standard (SAFE III) is still a proposal, and the rescission is EPA’s action rather than a restoration of DOT authority as such.
Litigation is the open question and cannot be closed from here. Petitions for review of an EPA rule go to the D.C. Circuit, which is outside the bulk docket snapshot; the snapshot itself stops at 2026-06-30 and both CourtListener search quotas were exhausted on 2026-09-01. Silence in the Corpus after that date means unknown, not nothing, so no blocked event is recorded and none is ruled out. Re-check before the consistency pass.
Shares p. 628 with #1718 (reduce CAFE to the MY2020 level, partial) and sits beside the California waiver items #1720 and #1721 on p. 629. #1718 owns the CAFE numbers and the SAFE III sequence; this item owns the EPA-side rescission. The 2025-06-11 interpretive rule is cited in both deliberately — it is the same document doing different work for each ask. Confirmed as not double-counting in the ticket 26 phase 2 page-seam review (2026-09-01): the interpretive rule is what carries #1718 to attempted (legal groundwork for lower numbers, no number changed), while it is corroboration here and the rung is carried by EPA’s final rescission of 2026-02-18, an instrument #1718 does not rely on. Neither item’s Status rests on the shared document alone.

Action: restore
Object: DOT/NHTSA authority over fuel economy standards under EPCA
ID: 1719