From Treehugger 

We previously reported on Jeff Rubin of CIBC World Market's prediction of gas costing $7 to $10 per gallon in four years; Now Rubin makes his prediction of its impact.

Over the next four years, we are likely to witness the greatest mass exodus of vehicles off America’s highways in history. By 2012, there should be some 10 million fewer vehicles on American roadways than there are today—a decline that dwarfs all previous adjustments including those during the two OPEC oil shocks.

Rubin notes that over 57 million Americans have access to public transit, and that more and more of them will use it, starting to "act more like Europeans", starting with lower income people.

Our analysis suggests that about half of the number of cars coming off the road in the next four years will be from low income households who have access to public transit. At their current driving habits, filling up the tank will have risen from about 7% of their income to 20%, an increase that will see many start taking the bus.

The Wall Street Journal writes:

Gas prices already appear to be reshaping suburbia. But what Mr. Rubin is predicting is a far bigger shock to the American system. Europe has had decades to develop a society based on expensive energy. What will happen if Americans suddenly are forced to shoulder European-style energy prices — but without the European-style society to cope with them?