Cars should be taxed based on their potential for road wear, which is calculated approximately by their weight to the fourth power.
Road wear comes from weight and power, so does pollution. Add size to the equation and you can estimate a cars dangerousness. Look only at size and you can see a cars damage to urban spaces. Hence, private vehicles should be taxed based on their size, weight and power. Bonus points for tire width, because tires are a non-recycable environmental problem and super-wide tires add nothing to the world but damage.
Road wear comes from weight and power, so does pollution. Add size to the equation and you can estimate a cars dangerousness. Look only at size and you can see a cars damage to urban spaces. Hence, private vehicles should be taxed based on their size, weight and power. Bonus points for tire width, because tires are a non-recycable environmental problem and super-wide tires add nothing to the world but damage.