Excuse me, this has been posted before. Here is a good artickle:
http://www.pennenergy.com/index/petroleum/display/3218778159/articles/oil-gas-financial-journal/unconventional/shale-gas__global.html
And if oilprices stay above 100$
I dont know what happens, but I can't load this site: www.nrcan.gc.ca/media
They post about the most energy efficient cars and I looked earlier that it is CNG/LNG cars.