Increasing fuel prices will only incentivize people to drive less if there are alternative means of transportation. Those are absent in most parts of the US.
You could double the price of gas in the US and driving would not change much, because people would have no other way to get to work and get their kids to school. The most you could hope for is that people would buy more efficient cars.
Maybe a similar situation is traffic in large cities, if time = money then there's an increased cost to driving during rush hour. Yet most people clearly chose to pay this price rather than trying to structure their life around cheaper (less time consuming) hours.
You could double the price of gas in the US and driving would not change much, because people would have no other way to get to work and get their kids to school. The most you could hope for is that people would buy more efficient cars.