The ratio is tricky. We don't really need vehicles to potentially carry more people -- we need folks to buy smaller vehicles. If we try to penalize people for

The ratio is tricky. We don't really need vehicles to potentially carry more people -- we need folks to buy smaller vehicles. If we try to penalize people for buying a two-seater truck, they'll just buy an even bigger extended cab with more seats. This is pretty much the exact kind of metric game the article cites as causing these giant trucks in the first place -- companies were penalized for building small fuel-inefficient trucks, so they just built big fuel-inefficient trucks that weren't penalized as much.