I keep hearing all these ancedotes about people driving less, etc but I think in reality it's a lot like dieting. One day you resolve that you are going to eat less and you do, the next day you probably still muster enough will power to keep your word, but over time you make little excuses (I need it, I deserve it, etc). By the time you look at the scale, you have actually gained a little weight, even though you claim to be "on a diet". Let's wait to see the data before we believe the ancedotes or polls saying people are driving less.

You have to make wholesale changes to your life - sell the SUV, buy a compact car/hybrid, carpool, combine trips, bike/walk more, move closer to work, take mass transit, etc. You know the drill.

How can selling your SUV save the world any gas? You must be assuming that the new owner will drive fewer miles than the old owner. Where is the evidence that used car buyers drive less than new car buyers? The solution to the SUV problem is not buying new ones.
Right, so if you flood the market with used SUVs, that will naturally make new SUVs less appealing - they get recycled.

But what I was really suggesting was that if individuals want to be less exposed to higher gas prices, those are ideas on how to reduce it, but it works at a national/global level too.

If you sell your SUV, the buyer may be one who was considering a new SUV. Also, if the market is flooded with SUVs, this drives down the resale value of SUVs, and indirectly, the amount people are willing to pay for new SUVs, thus decreasing the profit auto manufacturers realize from SUVs, thus prompting them (maybe) to build fewer SUVs and to build a greater number of fuel-efficient vehicles.

Agreed, the effect is small, but if enough people do it, it is there.