The assumption is that high fuel prices will drive the growth of mass transit and less reliance on "personal transportation". So if we had the well developed mass transit of Europe and $9/g gas, what would we expect? Well according the World Bank it could be higher car per capita rates as observed in Italy, Germany, Austria and Switzerland. Even the liberal France is within 2% and environmentally conscious Scandinavian countries with $12/g gas and up to 100% tax on new car purchases are only 10-20% less than the US.
http://www.nationmaster.com/graph/tr...portation-cars

This article can be seen as representing one side of the political spectrum. As there are just as many who see the upside of high fuel cost as a reason to drill in ANWR or off the Florida coast and open new distilleries and nuclear plants. Be careful with your glee for high gas prices.