Gas prices are rising at a time of year when they normally decline. Factor in the oversupply of oil and that makes this phenomenon even stranger. what's behind this unusual pattern? The decline of the dollar.

The price of oil is typically tied to the U.S. dollar in trading around the world. That means we're seeing a big run-up in price as our dollar weakens against other currencies. It's a consequence of the reality that the world is losing faith in how we keep our own economic house.

You can't really control what you pay at the pump -- other than by comparison shopping for the lowest-priced gas. The national average right now is $2.70 versus $1.60 one year ago at this time.

Economists who follow oil say that eventually the oversupply will win out over the weak dollar, and that's when the price will come back down. But you can't control when that happens either.

What you can control is how you buy a vehicle. Try buying cars that get more miles per gallon rather than cars that have an impressive number of horses under the hood. Four-cylinder vehicles -- like the coming Toyota Sienna minivan -- may be ideal for many Americans because you get a large vehicle that's also fuel efficient.

Consider going from V8 to V6 or even trying out a four cylinder.

Expect many midsized cars to drop from V6 to four cylinders going forward. In Japan, the No. 1 car for 2009 was the Toyota Prius. How amazing that a hybrid can be the leader in a major auto market.