I've had this theory that we will soon reach a point where rising gas prices will result in a significant reduction in traffic. The demand for gas is inelastic, yes, but not absolutely. Demand will diminish if prices get too high. The question is how high. The turning point will be when a significant number of people can't afford to fill their tanks as opposed to just grumbling about the price. I've witnessed people at gas stations giving the cashier only $20 and even $5.
The reason I bring it up now is that the LA Times just ran a piece that discuss this and, albeit based on anecdotal evidence, some feel that traffic has lessened. My gut feeling was that $5.00/gallon was the magic number. That would be $100 for a 20-gallon fill up. Once we start approaching and passing the 3-digit fill-up price, people on a large scale will start cutting back.
Unfortunately, I think we will soon find out if I'm correct.