Fuel Choice Act Grants 8 MPG Bonus to EV Makers, Legalizes Aftermarket Conversions

The Fuel Choice and Deregulation Act of 2025 is looking to shake up how we fuel our cars and how the government measures compliance for automakers. At its core, this bill does two big things: it loosens regulations around switching existing cars to run on alternative fuels, and it hands out a significant regulatory bonus to car manufacturers who commit heavily to non-petroleum vehicles.

Your Mechanic Can Now Convert Your Gas Guzzler (With Caveats)

Section 2 addresses the long-standing issue of modifying vehicles under the Clean Air Act. Right now, converting a gasoline car to run on something like natural gas after it leaves the factory could be considered "tampering" with emissions controls. This bill changes that. It says that aftermarket fuel conversions—like switching your pickup truck to run on compressed natural gas (CNG)—won't be considered tampering, provided the company doing the conversion can prove their technology is sophisticated enough and, critically, that the conversion doesn't make the vehicle pollute more than it did before the change. The person doing the work has to slap a label on the vehicle explaining the change. Essentially, the bill legalizes a new market for fuel conversions, but the EPA still has the authority to shut down any system that proves to be a dirty setup. For anyone who drives a lot or works in a fleet, this could open the door to cheaper fuel options, but the long-term reliability and environmental impact will hinge entirely on how strictly the EPA enforces that "no worse pollution" rule.

The 8 MPG Bonus and the Regulatory Fast Lane

Section 3 is where the real regulatory fireworks happen for the big automakers. The bill creates a new category: the "Fuel Choice Enabling Manufacturer." To qualify, a manufacturer must ensure at least 50% of the cars they sell in the U.S. are vehicles that run on alternative fuels—think plug-in electrics, hydrogen, natural gas, or high-blend ethanol (E85). If a company hits this 50% threshold for model year 2026 or later, they get two enormous advantages.

First, they get an 8 miles per gallon (MPG) bonus added to their calculated average fuel economy. Imagine a manufacturer is required to hit 45 MPG. If their actual fleet average is 40 MPG, but they qualify as a Fuel Choice Enabling Manufacturer, the government calculates their score as 48 MPG (40 + 8). This massive bonus makes hitting fuel economy targets significantly easier for these companies. Second, if they meet the fuel economy standards, they are automatically compliant with all the EPA’s greenhouse gas emission rules under the Clean Air Act. This means they bypass a whole layer of separate environmental compliance testing and regulation that other manufacturers still face. While this strongly incentivizes carmakers to push alternative fuel cars, it also means the EPA loses some regulatory oversight over the biggest players in the market.

What This Means for Your Wallet and Air Quality

For the average person, this bill introduces a trade-off. On one hand, the deregulation of aftermarket conversions (Sec. 2) could lead to more affordable fuel options and innovation in non-petroleum vehicles. A small business owner with a fleet of vans might save significant money by converting them to run on cheaper natural gas, for example. On the other hand, the massive regulatory break given to large manufacturers (Sec. 3) raises eyebrows. The 8 MPG bonus is so large that it could potentially allow these companies to sell more gas-guzzling vehicles alongside their EVs, effectively offsetting the environmental benefits of the EVs, while still meeting the letter of the law. If that "no worse pollution" clause on conversions isn't tightly regulated, we could also see more localized air quality issues from poorly executed conversions. The bill also explicitly protects "biomass fuel" from EPA control, regardless of any potential environmental concerns, which removes regulatory flexibility for future issues.