Not necessarily, you could just tax based on weight thresholds, established in legislation, in the same way you could ban vehicles based on the same factors.
The fuel NHSTA has over 1200 pages on just the new fuel economy rules. And there are dozens of agencies car manufacturers have to contend with to design a vehicle.
In unrelated news, average new car prices in the US climb to 48k while China has a new car under 10k
In unrelated news, average new car prices in the US climb to 48k while China has a new car under 10k
https://www.caranddriver.com/news/a39617404/nhtsa-fuel-econo...