Trump Rolls Back Biden Fuel Economy Standards, Targets 34.5 MPG by 2031

What Happened

President Donald Trump announced on Saturday, September 26, 2026, via Truth Social that he had approved new Corporate Average Fuel Economy (CAFE) standards reversing the Biden administration's 2024 final rule. The Biden rule, finalized in 2024, required automakers to achieve a fleetwide average of approximately 50.4 miles per gallon by model year 2031, up from 39.1 mpg at the time of adoption. Trump characterized the Biden standards as an "EV mandate" and claimed his new standards would "TERMINATE" what he called the "green new scam," arguing they would lower vehicle prices and bring manufacturing back to states including Michigan, Ohio, Indiana, and South Carolina. Transportation Secretary Sean Duffy reposted Trump's announcement and indicated a formal announcement would come Monday, September 28. The president did not release the final rule text on Saturday, but in December 2025 he had proposed a standard of roughly 34.5 mpg for light-duty vehicles by 2031 — more than 30 percent lower than the Biden target.

What the Evidence Establishes

The CAFE program, established by Congress in 1975, requires manufacturers to meet average fuel economy targets across their fleets, not to produce or sell any specific vehicle type. No federal statute or regulation has ever required consumers to purchase electric vehicles or prohibited the sale of gasoline-powered cars. The Biden administration's 2024 rule projected reduced fuel consumption and emissions while saving motorists money at the pump; automakers responded by accelerating EV production to comply. The Republican-controlled Congress eliminated federal EV consumer tax credits in 2025 as part of the One Big Beautiful Bill Act. Trump's December 2025 proposal of 34.5 mpg by 2031 represents a significant weakening relative to the 50.4 mpg target. General Motors, Ford, and Stellantis have publicly stated they will continue EV production regardless of federal standards, though weaker CAFE rules reduce the regulatory pressure to do so. The administration has not published the final rule's specific numeric targets, compliance flexibilities, or effective dates.

Where the Accounts Conflict

Trump and Republican allies consistently label the Biden CAFE standards an "EV mandate," a term the Al Jazeera and CNBC reports both note is inaccurate because the regulation sets fleetwide averages without prescribing powertrain mix. The administration claims the rollback will save families "thousands" on new vehicles and trigger over $100 billion in domestic auto investment, but neither the social media post nor the CNBC report provides a cost-benefit analysis, supplier commitments, or plant-level investment announcements to substantiate those figures. Automakers including GM and Ford have told reporters they intend to continue EV programs, contradicting the implication that the rollback will halt electrification. The CNBC report notes weaker standards enable more profitable pickup and SUV production, which have lower fuel economy, while the Al Jazeera piece highlights the growing gap between U.S. policy and global trends toward stricter efficiency standards in Europe and China. The final rule text, expected Monday, will determine whether the 34.5 mpg figure from December 2025 holds or whether the administration adopts a different target.

Context and Stakes

The CAFE rollback is part of a broader Trump administration effort to unwind Biden-era climate and energy policies, including the elimination of EV tax credits and the withdrawal from international emissions agreements. The U.S. auto industry employs roughly 1 million workers directly and supports millions more in supply chains; Michigan, Ohio, Indiana, and South Carolina are key electoral battlegrounds where auto manufacturing concentration is high. Weaker fuel economy standards reduce compliance costs for Detroit Three automakers in the near term but may weaken their competitive position in markets with stricter standards, including the European Union (targeting 100% zero-emission new cars by 2035) and China (where NEV penetration exceeded 50% in 2025). California and other Section 177 states retain authority to adopt stricter standards under the Clean Air Act waiver, though the Trump administration has previously challenged that authority. The financial impact on automakers depends on whether they maintain dual fleets for different regulatory regimes or consolidate around a single global platform strategy.

What to Watch Next

The formal rulemaking notice expected Monday, September 28, from the National Highway Traffic Safety Administration (NHTSA) will reveal the final 2027-2031 CAFE targets, any phase-in schedule, and the treatment of credit trading and off-cycle provisions. Environmental groups and Section 177 states are likely to file litigation challenging the rollback under the Administrative Procedure Act and the Energy Policy and Conservation Act's "maximum feasible" standard. The Congressional Review Act could be invoked by a future Congress to overturn the rule, though that would require unified party control. Investors should monitor Q3 2026 earnings calls from GM (NYSE: GM), Ford (NYSE: F), and Stellantis (NYSE: STLA) for capital allocation signals — specifically whether EV program spending is maintained, reduced, or reallocated to internal combustion lines. The UAW contract expires in 2028; the union's position on the rollback will influence labor negotiations and potential strike risk. NHTSA's regulatory impact analysis, when published, will provide the agency's own estimates of fuel savings forgone, emissions increases, and consumer cost effects.

Bottom Line

President Trump has directed a rollback of federal fuel economy standards to approximately 34.5 mpg by 2031, a 30 percent reduction from the Biden administration's 50.4 mpg target, framing the move as a consumer price reduction and manufacturing stimulus. The final rule has not been published; the numeric target, compliance mechanisms, and legal reasoning will determine its durability in court. No federal "EV mandate" exists or existed — the Biden rule set fleet averages that manufacturers could meet through any technology mix. Automakers have signaled continued EV investment regardless of federal standards, but weaker CAFE rules reduce regulatory pressure and improve near-term profitability of high-margin trucks and SUVs. The policy divergence from major global markets creates strategic risk for U.S. manufacturers if they delay electrification relative to foreign competitors. Litigation from states and environmental groups is virtually certain. The Monday NHTSA notice and subsequent regulatory impact analysis will provide the first concrete basis for assessing the rule's economic and environmental consequences.