VMT stands for Vehicle Miles Traveled. Check out this very interesting chart on VMT
(click to enlarge):
You'll note the cycling between the "driving season" and the winter, plus the steady average increase over time. It's also important to note the fuel efficiency has not improved over this same time period.
What is fasinating about this graph is the red line, the twelve month moving average. Notice at the far right hand side of the chart what happened last year when gasoline prices went up into the pain zone.
People cut back their driving and use of oil quite significantly. OPEC knows this. The oil companies know this. That's why the increase in oil prices are done in a step/adaptation fashion. Go too fast with a price increase and you kill your market. Go to slow and you don't maximize the income from your commodity.
Just like a good pimp.
This is simply a smart business practice. Which is why government has to play a role in our oil dependence. If we're ever to be serious about energy independence, the market will have to be used to motivate people and businesses to energy efficiency and energy innovation. A stepped up gasoline tax that continually keeps consumers at the pain edge of prices, without killing the economy, is what it will take to spur conservation and innovation. If we don't do it artificially, peak oil will see to it that we do it with oil depletion and it just might not be quite so smooth.