Okay - see that now. Reason I wrote that I kinda remember a while back were some politico was talking about lost tax revenue when gas prices would go down. Guess he thought the same thing too.
There is lost revenue when you have more fuel efficient cars. And that is sort of a problem, because those cars will still drive on roads the same number of miles and those roads will still wear out (needing maintenance and repairs) - but less money comes in for doing that. Electric cars basically get a “free ride” - so to speak.
Perhaps he was talking about less revenues - stemming from that.
Just for an example ... let’s say that everyone was driving 15 MPG cars one year — and then next year everyone was driving 30 MPG cars. Immediately, the governments would get ONE-HALF the tax revenue if people drove the same number of miles. To get the exact same revenue that second year, the governments would have to DOUBLE the tax just to remain the same.
When cars get more gas mileage the revenue goes down, which is causing some to consider a tax per mile driven.