If you drive a car, you know from pain these days. But it will get better. History suggests that the worst of the pinching at the pump will soon be over. The 12.9% spike in gas prices over the past month, to a national average $3.21 a gallon from $2.86, is a little bit higher than average for spring price movements. But it will end.”Prices tend to level off around Memorial Day,” says James Beck, a senior economist with the American Petroleum Institute. Still, expect $3 a gallon gas through the travel-heavy summer months as the U.S. hits the road. Statistics from the Federal Highway Administration show that driving does in fact pick up from May through August before tapering off, with February usually the least-traveled month. News source: Forbes.com Last June Americans logged 260 billion vehicle miles, about what they had logged a year earlier. That number stayed fairly steady through August, before declining to 241 billion vehicle miles in September, and then gradually falling to 215 billion miles by February, according to FHA data.Tips For Traveling What to do about gas prices until then? Consumer groups have many handy hints. How about changing your air filter? A clean filter typically shaves 28 cents per gallon off your gas bill. You can save another four cents a gallon just by cleaning extra junk out of the trunk–every 100 pounds of weight cuts fuel economy by 1% to 2%. Also, Consumer Reports says the notion that any car runs better on expensive premium Fuel is a myth, so feel free to keep more money in your pocket by avoiding it.Also:Straighten those wheels: Poor alignment forces the engine to work harder and wears the tires down more quickly, reducing gas mileage by as much as 10%.Tune up: A tuned engine can improve mileage 4%, to about 11 cents a gallon.Pump the tires: Nearly 25% of cars are running on improperly inflated tires, costing the average motorist eight cents a gallon in lost fuel economy.Check your gas cap: An estimated 17% of cars have broken or missing gas caps, which cost 2 cents per gallon.Lose the Canoe. At highway speeds, more than 50% of engine power is used to overcome wind drag. Consumer Reports tested a Toyota Camry sedan and a Mercury Mountaineer SUV with a Thule Cascade car-top carrier. It lowered the Camry’s gas mileage to 29 mpg from 35 mpg, and it lowered the Mountaineer’s gas mileage to 20 mpg from 21 mpg.Also worth noting: Conventional wisdom holds that air conditioning drains the fuel tank faster, but Consumer Reports found it reduces fuel economy by about one mile per gallon. Ditto the myth that opening the windows causes wind drag. Consumer Reports test drove cars with windows open at 65 mph, and the effect was “not even measurable.”Avoiding Tax Traps The other big thing you can do to save on gas: Be careful where you buy it. Those who know where to stop for gas can save a bundle over the course of a long trip by avoiding states with high taxes. If you’re tooling around New England, try to avoid filling up in Connecticut, a high gas tax state where regular goes for $3.28 a gallon, or in Maine, where it sells for $3.11 a gallon, according to the latest AAA numbers. Opt for New Hampshire or Vermont, where its costs just a penny or two over $3. Exploring the mountain west? A thinly spread population makes gas in that region expensive. Wyoming, with an average of $3.18 a gallon, offers the best deal. Try to steer clear of gas stations in Montana and Utah, which both charge about $3.26 a gallon, or Colorado, where it shoots up to $3.34.Up and down the Atlantic coast, skillful state hopping can save a bundle. By all means, wait until you get though New York and its $3.22 per gallon price tag to fill the tank in New Jersey, where it drops to $2.95 (and where the extra mile or so off the state turnpike to avoid rest stop prices is worth it). After that, bypass Maryland ($3.13 a gallon) in order to load up in Virginia ($3.06), making sure to get enough to take you through the expensive state of North Carolina in favor of South Carolina (the price drops to $3.01 a gallon from $3.15 after crossing the border at the Carolinas). And of course, don’t ever buy gas in California unless it’s absolutely necessary. The high demand stemming from a driver-centric population, together with high taxes, makes for an average price of $3.44 per gallon in the Golden State. Crossing into Nevada or Arizona for gas will save anywhere from 18 cents to 34 cents a gallon (though prices to the north in Oregon aren’t much cheaper).Why So High? Why are gas prices so high? It isn’t just the driving. Data from the past decade shows that springtime, when refineries hit their low output turnaround schedule as they switch their concentration to Fuel from heating oil, brings the biggest price increases of the year.A look at price history since 1997 shows that gas costs an average of 10.2% more during the April-May period than it does during the colder stretch of December through March. The prime summer months of June, July and August add just another 1.4% over springtime prices, the numbers show, before retreating 5.4% during the fall and winter months. So those who have managed to get used to the big uptick in gas prices over the past couple of months shouldn’t suffer from much additional sticker shock as the warm weather season progresses. With refineries having production problems this spring, thanks to a list of unlikely problems that included fire and animal sabotage, unscheduled outages became the norm, according to the API. And despite a survey of March numbers showing individual demand dropping at the highest clip since the gas-line year of 1980, the growth in driving age population has kept overall demand high.It doesn’t mean you can’t enjoy the road this summer. Just tune up the car and clear out the trunk, and take heart in the likelihood that prices won’t get much worse than they already are. At least not this year.