Gas prices are unbelievably low in the US compared to almost everywhere else. We are crying because it is now over $3 US per US gallon. The conversion is a bit complicated, but that works out to something like £0.5 per liter. It isn't exactly subsidized, but it is almost untaxed. This chart shows gas/petrol prices from about 6 months ago - the base price doesn't change much from one country to another, but the tax rates (and thus the overall cost) vary dramatically.