I came across this graph. It's breaks down how gas prices effect the amount of driving and it goes back to 2002. The graph itself is a little tricky to read, but the information is there.
isn't that so interesting? the most insane thing is how tightly tied to politics the price of oil is. like michael boone said, foreign oil shouldn't be continually used as we transition to alternative energy - if a nation that doesn't particularly like as at any point decides to enforce an embargo, we're basically crippled.