Can you drive 1,000 miles in your car and spend less than $60 on fuel? That's the beauty of the Volkswagen Sportwagen TDI diesel, which averaged 43 mpg. It runs forever on a gallon of fuel, entertains you while under way, cruises comfortably at speed, and holds tons of gear. The wagon, which I tested, and the Jetta TDI sedan, belong on your new-car shopping list if you do a lot of highway driving. They'll hold their own against hybrids that do best in city driving.

The Jetta SportWagen TDI (VW spells it SportWagen) is rated at 29 mpg city, 41 mpg highway with the six-speed double shift gearbox (DSG), an automated manual transmission that shifts the gears for you. (No clutch pedal.) The Jetta TDI sedan is rated the same. The 2010 Toyota Prius hybrid, a somewhat smaller car, is rated at 50 mpg city, 48 mpg highway. I got 43 mpg on my mostly highway trip. While 50 mpg seems a magical number, economy gains aren't linear (43 mpg to 48 mpg isn't as big a gain as 23 mpg to 28 mpg). In practical terms, the difference between the Jetta TDI and Prius over 12,000 miles of highway driving is about 25 gallons of fuel per year. In terms of fuel used, this is definitely a green car.

On the Road: You'll (Almost) Never Know It's a Diesel
Forget everything you know about diesel cars from your trip to Europe 10 years ago, or from seeing out-of-tune trucks belching soot here in the U.S. Today's diesels start immediately and sound almost exactly like gasoline engine cars. From the outside, you'll hear a bit of clatter when it starts, especially in cooler weather. From outside, you may catch the faintest whiff of diesel fuel but that's all, thanks to the mandatory ultra-low sulfur fuel and on-board emissions gear.

Inside the Jetta , you have to listen hard to tell it's a diesel. I used to say you couldn't tell at all. Actually, you can at low speeds, with some cars, including this Jetta. But once you reach 30 mph, you just can't tell, and neither can anyone on the street. In fact, the Audi diesel racecars that won LeMans with boring regularity (until this year) were the quietest cars in the field.

The combination of the 140-hp turbo-diesel engine and the six-speed DSG gearbox makes for passable acceleration: 9.5 seconds 0-60 mph. Other VWs with DSG transmissions offer paddle shifters; many owners never use them, but some do, and it does make a station wagon feel a bit racier. I missed them.

What About Diesel Filling Stations?
You may have to bypass one gasoline-only station to find diesel at a second. More stations have diesel near highway interchanges. Because it's not certain there'll be diesel at the nearest station, you don't want to run too close to empty. VW has a 14.5-gallon tank, theoretically good for 624 miles at my 43 mpg. But the fuel pump can't always reach the last gallon in the tank, so treat this car as having 12.5 gallons of useful capacity, still good for 500 miles at 40 mpg. The Jetta's navigation system has a POI (point of interest) button that finds the nearest diesel stations.

Diesel fuel is essentially the same as jet fuel, kerosene, or home heating oil (don't substitute them, though), with about 10% more energy per gallon than gasoline, and about 50% more grime around the fuel pump. Minor drips from the nozzle don't evaporate the way volatile gasoline does, so a dark, oily residue builds up on the nozzle, handle, and around the dock in the pump. It would be helpful to diesel's image if gas stations sent someone out with a rag a couple times a day to wipe down the diesel pumps. You may want to keep a box of disposable plastic gloves in the glovebox so your hand doesn't smell.

Good Audio Choices (But Where's iPod? Where's Bluetooth?)
Order the $1,990 navigation system and you get a great display for showing audio choices (radio presets, upcoming songs on the playlist). My test car had a CD changer, Sirius satellite radio (standard on virtually all Jettas), line-in jack, an SD-card slot, a hard disk with 20GB free for ripped audio, and a USB connector that worked with USB memory keys. The VW website said an iPod adapter ($199) isn't available if you order navigation, but the build-your-own part allowed us to select both. Our test car had a USB jack that made a physical connection with two iPods, but neither were recognized by the head unit.

The navigation system worked well and could be operated while the car was under way. There was a traffic setting on the navigation system, but what it meant was: If you run into heavy traffic, push this and we'll create a detour. It wasn't a real-time traffic information monitor. When I'm in a car with RTTI, I always curse how often it's slow to see traffic jams or misses them - but not as much as I curse a car with no real-time traffic information at all.

Bluetooth is available as a dealer-install accessory for $341 plus installation, which is too costly. VW erred by not making this standard, or at least a cheaper option. Cars shouldn't be sold without Bluetooth. Backup sonar also is a dealer-install accessory.

The Jetta also has an MID, or multi-information display (photo left), between the speedometer and tachometer that functions much like a head-up display, except you have to glance down just below the top of the steering wheel, rather than look to the base of the windshield. You could toggle among navigation directions, audio, and trip computer displays. The MDI audio display could be slightly better: When you're using satellite radio, it tells you the channel and artist but not the song.

Little Glitches
On my test car at least, there were a couple issues that undercut the basic goodness of the Jetta design:

The audio system seemed bright - too much treble, voices hard to hear on talk radio, no matter how you adjusted the speaker position and the equalizer.

The radio knobs were slippery, chrome-looking midgets that weren't easy to grasp. German automakers often use a grippy rubberized black coating on knobs and it would have been appropriate here.

The air conditioner just kept up with 90-degree temperatures. Other vehicles got cooler quicker.

The grab handle on the center console is a cool design, but it makes for a sharp-edged knee rest on long trips. Other cars have a piece of padding there, or create a softer angle where your knee touches. 

The steering wheel has no buttons - zero, none, nada - forcing you to rely on the turn signal and wiper stalks to set the cruise control and switch among MID settings, or use those slippery radio knobs.

The ignition switch is on the steering column and even a short key fob drops down and tickles your knee while driving. Much as people gripe about push-button start buttons on the dash, they do allow designers to move the key up and out of the way.

The navigation screen for route preferences was nearly impossible to decipher. You couldn't tell if a setting was on or off and on a trip to ball park 55 miles away, the system choose a circuitous 125-mile route to avoid toll roads, which was inadvertently deselected as a route choice.

Bottom Line: Roomy, Economical, Less than $30K
The test SportWagen TDI was equipped with the DVD navigation system, a gorgeous 54-inch deep panoramic sunroof with glass panels extending all the way past the rear seat (and a translucent sunshade) for $1,300, the DSG gearbox ($1,100), and alloy wheels ($450). The seats were vinyl, not leather (not available), but they didn't seem clammy, unlike some other vinyl-seat cars I've driven lately, including a BMW. Sticker price with shipping was $29,410. That buys you a car with a good back seat and a huge cargo bay, better than on a lot of $45,000 SUVs. And the ability to drive all day without stopping for fuel.