The road to fuel efficiency seems to many to be best traveled by hybrids. But there are alternatives. Six- and seven-speed automatic transmissions. Cylinder deactivation that automatically decreases the number of cylinders when cruising.

And many auto experts say cars powered by diesel fuel may prove to be the more viable option for attracting consumers in coming years. But there's a big roadblock: pollution and health issues.

	Jeep The diesel-powered Jeep Liberty, which starts at $22,600, puts out 160 horsepower and gets 22 miles per gallon in the city and 27 on the highway. Click photo for larger image.

Medical and environmental experts have known for years that diesel exhaust can cause a number of health problems, and that metropolitan areas with higher emission concentrations from diesel exhaust have higher death and illness rates. The good news is that tighter emissions rules and cleaner fuel standards are on the way for 2007.

One alternative now on the market is the diesel-powered Jeep Liberty, which starts at $22,600. The price can go as high as $25,970 after adding an automatic transmission, power sunroof, speed control and other items, but given the rebate programs available and dealers' willingness to deal, chances are good that you will pay less.

The turbo diesel engine, which is an enhanced version of a four-cylinder diesel engine currently offered on the Liberty in Europe, puts out 160 horsepower and 295 pound feet of torque, a prodigious amount of torque for the Liberty's size. Fuel economy is 22 city and 27 highway, an average of 30 percent improvement over the nondiesel engine, with a 20 percent reduction in carbon dioxide emissions.

When you start the Liberty diesel you hear some of the clankety-clank noise that people associate with diesel-powered cars. But after a few seconds, all is quiet as the engine settles down. On the road, you barely notice the difference in noise level, nor do you the stinky smell that people associate with diesels.

The Liberty is a rugged, small- to midsize SUV that enjoys a good reputation among off-roaders and consumers alike. The Liberty has a coveted "Recommended" designation from Consumer Reports, as well as honors from a number of other automotive sources.

It's really not difficult to understand why the Liberty is so popular. First, it has an eminently manageable size for urban driving, which is something you can't say for every SUV.

Secondly, it has an attractive, up-to-date cabin that has reasonable room for five. It has a long list of models, options and packages, so you're sure to find something that will express just what you want.

And in the Jeep lexicon, it is "Trail Rated," which means it meets standards in five categories: traction, ground clearance, maneuverability, articulation and water fording.

When the Liberty was first introduced several years ago, I liked it but found that its ride and handling characteristics were a bit skittish. All of that is gone now, thanks to improvements to the platform and suspension system. It feels stable and secure with only a trace of the bounciness that earlier models possessed.

Unfortunately, what hasn't disappeared is the sticklike, floor-mounted lever for switching into four-wheel drive. I'm sure enthusiasts who go off-road love it, but for those of us who are not likely to do so, operating this lever can be cumbersome. I'd much prefer some sort of automatic four-wheel drive system.

On the whole, however, the Liberty is a strong competitor in the midsize SUV segment and you should consider it if you're in that market.