Wow, that's fantastic. Wish we'd do some such thing. Maybe keying high-emissions vehicles could become mandatory?

Unfortunately, I'm sure that even if the US did impose a tax on high-emissions vehicles, the money would go to something totally unrelated--nat. defense, or some such thing. Brings to mind that video a while back from CSPAN of that Republican congressman deriding a Democrat's idea that riding bicycles could POSSIBLY reduce CO2 emissions.