But older vehicles aren't taxed more...? You don't pay the BPM (new car tax) and the road tax for a 1000kg car from 1990 is exactly the same as a new 1000kg car

But older vehicles aren't taxed more...? You don't pay the BPM (new car tax) and the road tax for a 1000kg car from 1990 is exactly the same as a new 1000kg car. Also, the way the diesel scheme works is that there's a treshold so that it's only cheaper to drive diesels when you drive a lot of miles. Also, the heavier the car, the more miles you'd have to drive. But I'm sure you know this. And where exactly is 'money lost in the friction' here? Diesel prices are known, and tax brackets are pretty clear too. I agree that we shouldn't subsidize $100k+ Teslas, but I'm all for rewarding people to drive cleaner vehicles. And calling it the single most asocial rule in the world... well, that's kind of a hyperbole, don't you think? Related: I used to drive a 1986 Subaru Justy which ran 1:20 on regular fuel and costs next to nothing to insure and maintain. Cheapest form of motorized transport I ever had!