What Washington actually changed
The final rule replaces the Biden-era trajectory with a single fleet-wide target: 34.9 miles per gallon by MY2031 instead of 50.4. Alongside it, the CAFE emissions-credit trading scheme ends with the 2028 model year — the programme the department itself describes as having "artificially propped up the EV industry."
The most telling number comes from the regulator's own analysis. NHTSA calculates that a MY2031 fleet built to the new standard would be less efficient than the fleet already sold in 2024. That is not a forecast about some distant future; it is a statement that the bar is being set below where the market already stands.
It lands on top of an incentive shock. The federal purchase credit for new EVs expired at the end of September 2025, and US EV sales fell 28% year-on-year in Q1 2026. Ford, GM and Stellantis have since written down billions in their EV programmes and shifted capital back to combustion models — the 2027 Dodge Charger Scat Pack used as the illustration for this story is a petrol-engined car.
Our maths: what 34.9 mpg means in l/100 km
US mpg figures are the American cousin of WLTP — a regulatory test value, not something you will see on the trip computer. Converting them properly (1 US gallon = 3.785 l, 1 mile = 1.609 km) gives a clearer picture:
| Biden rule (MY2031) | 50.4 mpg | 4.67 l/100 km | 21.4 km/l |
| New rule (MY2031) | 34.9 mpg | 6.74 l/100 km | 14.8 km/l |
| Difference | −15.5 mpg | +2.07 l/100 km | +44% |
Treat that 44% with the usual skepticism, because CAFE compliance numbers include air-conditioning and off-cycle credits and are not the same scale as the EPA label on the windscreen, where the new-vehicle average has hovered around the mid-20s mpg in recent model years. The direction of travel, however, is not ambiguous: manufacturers have just been handed 2.07 litres per 100 km of headroom.
What it costs a driver
Take a US average petrol price of $3.20 a gallon — $0.845 a litre — and a driver covering 15,000 miles (24,140 km) a year:
- At the old standard: $3.95 per 100 km, or about $952 a year in fuel.
- At the new standard: $5.70 per 100 km, or about $1,375 a year.
- Difference: $1.75 per 100 km, roughly $420 a year — per car. Two cars in a household, and the rollback costs more than a set of winter tyres every year.
This is the arithmetic behind the Electrification Coalition's warning that the rule drives up costs for American families. Weakening a supply-side efficiency standard does not lower the price of petrol; it lowers the amount of engineering spent avoiding it.
An EV at home still wins per kilometre — on a fast charger it does not
Run the same distance on electrons. An 18 kWh/100 km crossover charged at home on the US average residential rate of about $0.17/kWh costs $3.06 per 100 km — cheaper than a car built to either standard. At a DC fast charger at $0.45/kWh, the same car costs $8.10 per 100 km, more than a petrol car under the 50.4 mpg rule. Any honest comparison has to hold both numbers, and you can run your own figures in our charging cost calculator or the EV savings calculator.
In Europe the gap is wider still, because fuel is taxed harder: at around €1.60 a litre, a 6.7 l/100 km car costs roughly €10.70 per 100 km, while the same 18 kWh/100 km EV on a €0.25/kWh home tariff costs €4.50. That is a structural difference no US rule can undo.
The credit market disappears in 2028
Ending CAFE credit trading from MY2028 removes a revenue line that has quietly mattered. Automakers that beat their target sell surplus credits to those that miss; Tesla has booked billions of dollars a year from exactly that mechanism — roughly $2.8 billion in 2024 alone. From 2028, over-compliance no longer has a buyer.
Meanwhile the technology race keeps moving in Asia. CATL's own data on 14-year-old LFP cells shows 85% capacity remaining — 1.1 percentage points of degradation per year — and BYD's next-generation platform is chasing five-minute charging. Capital that leaves EV programmes in Detroit does not return faster than capital that stays in Shenzhen.
Europe is heading the other way
The contrast with the EU is stark. In August, battery-electric cars took 29.2% of Europe's new-car market and outsold petrol and diesel combined, with the EU's zero-emission target for 2035 still on the books. Whatever happens to that target in review, Brussels is not currently in the business of lowering the bar.
What a buyer should take from this
Nothing in this rule stops a US carmaker from building an efficient or electric car — it simply stops forcing the issue. So the burden shifts to the buyer: check real consumption rather than the regulatory figure, and work out cost per 100 km before cost per month. Our EV catalog and database of 483 European supercharger locations are there for exactly that kind of arithmetic, and the real-world range tool built on Bjørn Nyland's measurements is the closest thing to a winter-honest number we have.
Source: https://www.electrive.com/2026/09/29/new-fuel-consumption-regulation-sees-us-ev-adoption-slow/
