Looking for a car with a great highway fuel range? Here are 10 of the best.

With the summer driving season just weeks away, many new car buyers are in the market for a great road trip car - and a high overall gas tank range is definitely a major factor in determining which cars are best on the open road.

Looking strictly at a new car's fuel range doesn't necessarily give you a complete picture of its fuel efficiency, but it will help you effectively reduce the number of gas station visits. And for some drivers, that's all that really matters. After all, any car you'll find on our list below offers pretty impressive fuel economy for what it is. Otherwise, it wouldn't offer much of a driving range, even if its fuel tank is enormous.

We looked at every car currently available in United States showrooms to determine just which ones offer the longest driving range based on both the largest available fuel tank size specified by the automaker and the highway fuel economy achieved in EPA testing. The results run the gamut, so we've included a few metrics with each car listed.

A number of cars we expected to see on the list are missing because they have oddly small fuel tanks. For example, the large Chevrolet Malibu Eco is rated at 37 mpg on the highway, but its tank holds less than 16 milk jugs of unleaded. So too the 42 mpg Chevrolet Cruze Eco manual transmission, which holds a full three gallons less than its 39 mpg automatic brother. In part, the lighter fuel tanks probably help save a little gas.

In addition, heavy duty pickups and some SUVs didn't qualify since they are too heavy to be tested by the EPA. In our testing, we've found that the most efficient diesel-powered heavy duty trucks net at best 19-20 mpg on the highway, which should give most trucks a 700-plus mile range. If you happen to work in the oil industry and want to fund a large truck fuel range challenge, we're all ears!

Our findings were a tale of three stories. Naturally, diesel-powered cars and crossovers are strong highway performers, but only midsize and full-size models offer big fuel tanks. Then there were the pickups; although they guzzle fuel at nearly double the rate of a sedan, certain configurations offer gigantic fuel tanks. Finally, midsize hybrids are big enough to have larger fuel tanks than smaller, ultimately more fuel efficient hybrids like the Toyota Prius.

While we've only listed the top 10 here, a number of other vehicles nearly qualified: The Chevrolet Suburban (and GMC Yukon XL), the Toyota Camry Hybrid and the Audi Q7 TDI all missed out by just a few miles of overall range.

Which one best meets your needs for a road trip?

10 cars that go further on a tank of fuel

1. 796 miles - Volkswagen Passat TDI 6-speed

43 mpg, 18.5 gallons

With its nearly 800 mile range, the Volkswagen Passat TDI (manual transmission) is arguably the ultimate road trip car. Pick your route carefully and drive conservatively and that's enough to get you from Denver to Dallas or Phoenix, Atlanta to Philadelphia, or Seattle to San Francisco.

2. 756 miles - Ford F-150 EcoBoost 4x4

21 mpg, 36 gallons

If it's outright range you're after in a pickup, the F-150 EcoBoost 4x4 is your go-to vehicle since it's the only F-150 Ford offers with a 36 gallon fuel tank. The EcoBoost's 21 mpg is nothing to be ashamed of, either, although it matches a few other trucks and it's not as impressive as the 23 mpg a correctly-optioned 3.7-liter F-150 will net you. In this case, the big tank boosted this truck.

3. 740 miles - Volkswagen Passat TDI automatic

40 mpg, 18.5 gallons

Opting for the Passat TDI's optional automatic dents fuel economy, but a 740 mile range is still nothing to be ashamed of. Like the manual transmission car, the automatic Passat TDI boasts a 2.0-liter turbodiesel engine, a roomy interior and an ever-so-slightly German accent to its Tennessee assembly.

4. 739 miles - Volkswagen Touareg TDI

28 mpg, 26.4 gallons

VW's high-tech Touareg doesn't sell in big numbers in North America and that's a shame. This chunky four-wheel-drive midsize crossover is a delight to drive and it's pretty darn fuel efficient. With three engine choices on offer in the Touareg lineup - a gas V6, a diesel V6 and a gas hybrid - this one is our default choice.

5. 738 miles - Mercedes-Benz S350 BlueTEC

31 mpg, 23.8 gallons

Here's a trivia fact: In the early 1980s, Mercedes-Benz sold a bunch of diesel S-Classes in the U.S., but the model wasn't even offered with a diesel in Europe. Fast forward a few decades and the opposite was the case until late last year, when the S350 BlueTEC signaled the oil burner's re-entry into the Fifty Nifty.

6. 714 miles - Chevrolet Silverado 1500/GMC Sierra 1500 (5.3, extended cab, long bed)

21 mpg, 34 gallons

For fuel misers, GM's pickups offer three options: With the extended cab and a long bed, GM's big trucks offer a big 34 gallon fuel tank to make the most of their 21 mpg highway. Or, a smaller tank is included with the two-wheel-drive-only XFE (that's Xtra Fuel Efficent) Silverado and Sierra, which net 22 mpg on the highway. And then there's the hybrid, which improves things to 23 mpg but again includes the smaller fuel tank.

7. 688 miles - Hyundai Sonata Hybrid/Kia Optima Hybrid

40 mpg, 17.2 gallons

Essentially identical beneath the skin, the Hyundai Sonata and Kia Optima Hybrids are their Korean parents' first such offerings in our market. We're partial to the more Teutonic Kia, which was penned at the hands of a former Audi designer. We also think it has the nicer interior.

8. 675 miles - Mercedes-Benz E350 BlueTEC

32 mpg, 21.1 gallons

Mercedes-Benz's midsize lineup has been available with a diesel engine for an on-and-off four decades now, and the powertrain has never been more robust. Outright fuel economy isn't as strong as it used to be thanks to more emissions goodies mandated by the EPA, but this luxury sedan still makes a serious case for itself - especially when compared to the similarly-priced gas E350.

9. 670 miles - Ford Expedition EL 2WD

20 mpg, 33.5 gallons

The least fuel efficient vehicle on our list is also the largest: The Ford Expedition EL. Opt for sunbelt-friendly two-wheel-drive on your Expedition EL and you'll achieve as much as 20 mpg on the highway, according to the EPA. Only the extended-length model - that's the EL for you - includes a larger 33.5 gallon fuel tank that helps put it on our list.

10. 666 miles - Audi A8

28 mpg, 23.8 gallons

For 2013 Audi is set to add a new entry-level A8 powered by a 3.0-liter supercharged V6. Slotting below the current 4.2-liter V8, you'd think it would be the fuel economy leader... but that's not the case. Although the 3.0T (yes, that's a T for supercharged?) will cost less than the 4.2, it'll be rated at the same 18/28 mpg. That's pretty impressive for the V8, but a bit of a disappointment for the V6 - although the six will come with a start/stop system that should yield improved real world urban economy.