I can see why states with high concentrations of population want to reduce "polution", but most of the country is not densly populated. The truth is that the air quality has continually gotten better over the last century, mostly due to the fact that we don't burn coal or wood, plus over time our vehicles along with our manufacturing methods have become far more efficient.
That said, yes it is about PC and $$$$. As gasoline prices rise and more people buy "green machines", both federal and state governments, who by the way make more $$$ per gallon of gasoline than the oil companies, are studying taxing car owners by the mile driven as we speak.
