While the cost of gas does make it easier to do more travelling it hasn't changed my consumption at all. I'm guessing that even though the cost of gas is low right now people will still use the same or less (just my opinion).
I base this opinion on the idea that there are higher costs at the grocery store (my bill has gone up by about 30% with no change in my list), layoffs ect. The present economic situation has people scared about the security of their job and will be spending less overall.
Sad to say, but until an affordable alternative becomes available to the general population we really are slaves to the Oil and Gas Lords.
(Just as an FYI - When the weather permits I do use my feet and a bicycle for transportation)