For what reason?
It will likely be there in a few years.
monetary reason is the quickest way to motivate people..by artifically raising the price you will see tremendous changes in a short time.
1. By next year you won't see any more SUVs or personal trucks.
2. Manufactures will starts the cycle of creating super efficient cars.
3. It will make buying a hybrid/electric cheaper in the long run. The joke now is the hybrid cost more than gas, so buying one is not cheaper.
4. People will consider walking/riding bicycles from short trips if possible.
5. More people will look to mass transit. Which will lead to better and more efficient mass transport systems.
6. Reduce our dependency on oil.
I could go on and on on the benefits
in Europe they average 40mpg, the US average 24mpg. Price of petro clearly is motivativing factor.