You don't have to worry about SUV tax turning up in your tax returns (if you live in the U.S.). If we get a carbon law at all, there won't be any taxes on cars according to a House white paper on the topic. Most of the American presidential candidate's energy policies call for tax incentives, but not penalties. If if could be implemented, how much of a tax would it take to change sales of SUVs? Canadians, for example, are taxed $4,000 for driving an un-green car. Would that stop you from buying an SUV?