If americans do not want to limit fuel consumption now - then prices like 20$ per litre will do it for them later.
And then they will sell their hummers for scrap metal...

10 years ago fuel here was 3x cheaper than it is now.
In 2000 fuel (95 gasoline) price in Latvia was about 0,60$ per litre - now - 1,80$ per litre.
And it will not get cheaper.