1: https://en.wikipedia.org/wiki/Corporate_average_fuel_economy...
1: https://en.wikipedia.org/wiki/Corporate_average_fuel_economy...
1. Poorer people tend to drive older vehicles, so if you solely encourage higher fuel economies by taxing carbon emissions, then the tax is (at least short-term) regressive.
2. You can work around #1 by applying incentives for manufacturers to make more efficient cars should lead any carbon tax
3. If you just reward companies based on fleet-average fuel economy without regard to vehicle size, then it would be rather bad for US car companies (who employ unionized workers) that historically make larger cars than Asian and European companies.
4. So the first thing done was to have a separate standard for passenger vehicles and light-trucks, but this resulted in minivans and SUVs being made in such a way as to get the light-truck rating
5. We then ended up with the size-based calculation we have today, but the formula is (IMO) overly punitive on small vehicles. Given that the formula was forward looking, it was almost certain to be wrong in one direction or the other, but it hasn't been updated.
Every single one of your ideas has problems that are solved by a carbon tax. Taxes are simple, they accomplish what you want, and they don't have loopholes. A carbon tax will _never_ have the unintended consequence of making emissions worse. Many of our current regulations, including the one I was responding to do exactly that because they actually cause people to buy larger trucks than they otherwise would with worse fuel efficiency.
A carbon tax might not on it's own be enough to solve the problem (especially if you set it to low), but no matter what level you set it, it will help. Thanks to unintended consequences, many of our current regulations are actively counter productive, while _also_ having negative economic and other costs.
Why would you think so? People driving older cars, not being able to afford to fly - will certainly spend more money on fuel for their car.
Maybe they drive a more efficient car, but they own much larger houses which are heated or cooled consistently, they travel a lot more, and they buy things with embodied carbon emissions.
That's close to impossible to implement. You'd need to track production and usage of everything in an extreme detail. Plus tracking all purchases (items + services) to a given person. So complete state surveillance of citizens. Globally.