Updated on June 5, 2008.

BUMPER-TO-BUMPER TRAFFIC and gas prices at $4-a-gallon are a far cry from the road-trip ideal of the open road and the wind in your hair.

Here are some tips to help you survive sticker-shock at the pump and gas-guzzling on the road.

Finding Cheap Gas

OK, so truly "cheap" gas isn't likely with the national average at $3.98 a gallon. But because prices vary often dramatically from station to station, shopping around can cut your gas bill by up to 30%, says Jason Toews, co-founder of price-monitoring site

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In San Francisco, for example, prices for a gallon of regular currently range from $4.10 to as much as $4.69. You'd save 13% by pinpointing the bargain pump. "Even in the smaller cities, it's not uncommon to see a 30- to 40-cent difference between the highest and lowest prices," he says. Here's how to find the least expensive gas:

1. Time your trip
Gas stations tend to change their prices during the slow morning periods, usually between 10 a.m. and noon, says Toews. Aim to get there early if prices are on the rise. Wait until later in the day if prices are falling.

2. Conduct advance research
Of course, unless you're driving an RV, going out of your way negates any savings you might reap from that pennies-cheaper gas, cautions Mike Pi a, a spokesman for AAA. "Before you leave home, use mapping tools to find out where gas stations are along your route, and what they're charging," he advises. GasBuddy.com, AAA Fuel Price Finder and GasPriceWatch.com all use this technology.

3. Consider all options
When prices are high, which station has the best deal is a constantly changing free-for-all, says Toews. "It forces other stations to be more competitive," he says. Independents may have more leeway to cut into profits, while wholesale clubs like BJ's and Sam's Club use gas as a loss leader to drive customers into their stores.

Conserving Gas

Excellent fuel economy isn't solely reserved for hybrids. How you drive can be as important as your vehicle. Try these four tips to reduce your number of trips to the pump:

1. Tune-up
Before you hit the road, make sure your car is in tip-top shape, advises Juan Crespo, an ASE-Certified Master Technician with CarMax.com. Check the oil, air filter, transmission fluid and brakes, among other parts. Replacing a dirty air filter, for example, costs just $10, and may improve fuel economy by more than 20%.

No time for a trip to the mechanic? At least check that your tires are properly inflated. "The lower the pressure, the more of the tire surface is on the road," explains Crespo. "That increases friction, and uses more fuel." Your fuel economy drops 2% for every pound per square inch (psi) your tires are under-inflated, according to AAA.

2. Lighten your load
Think twice before over-packing for your next road trip, or letting your backseat double as a closet. "People think as long as all their stuff fits in the trunk, that it won't make a difference in fuel economy," says Jim Kliesch, a research associate at the American Council for an Energy-Efficient Economy. Not true. "It takes energy to move stuff around." Your fuel economy is reduced by 1% for every 100 pounds of weight (including passengers).

3. Mind your driving habits
and speeding tickets by driving within the speed limit, advises Kliesch. "Engines are designed to be most efficient in the 55-to-60 miles per hour range," he says. Going much faster or slower means you're using excess fuel. Just how much extra, you ask? Driving at 75 mph instead of 55mph reduces your fuel economy by an impressive 26%.

You'll also improve efficiency with consistent driving, adds Pi a. Quickly braking or accelerating burns extra fuel. An easy solution: Set the cruise control when possible.

4. Beat the heat the right way
From a fuel-efficiency perspective, there's no great way to stay cool when temperatures are sizzling, says Kliesch. Air conditioning decreases fuel economy by 20%, while open windows increase drag. Which one is the lesser evil? That depends on your driving situation. Air-conditioning is best for faster speeds and highway driving. But when you're stalled in traffic, or tooling around town at low speeds, use the A/C sparingly, he advises. "Just put the windows down."