Yup, weight is important for sure, and it is quite nonlinear. That could mean that most consumer vehicles don't vary that greatly compared with 18-wheelers. Sin

Yup, weight is important for sure, and it is quite nonlinear. That could mean that most consumer vehicles don't vary that greatly compared with 18-wheelers. Since those mostly use diesel, perhaps this could be roughly addressed by changing the tax on diesel fuel. But that would end up being terrible for the relatively small number of folks with diesel small cars (we once had a TDI Golf!).