( AOL Autos ) -- The 2008 Saturn Flextreme may be a concept, but it shows that General Motors is serious about putting advanced, fuel-efficient hybrids on American roads in the not too distant future.

Let's put the Flextreme in perspective. It's Saturn's follow-up version of the 2007's Detroit Auto Show concept hit, the Chevy Volt, and what's important about this Saturn is the progress that it demonstrates.

Looking at what's before you, it's conceivable that GM will have a vehicle based on its purpose-built eFlex hybrid platform and powertrain technology in dealerships. It could be as early as 2010-11.

Driving range after leaving the house with a fully charged battery pack and a full tank of ultra-low-sulfur diesel is estimated to be 444 miles. See other hot cars at show »

The ecologically minded plug-in Saturn features pure electric propulsion. One motor drives both front wheels. The on-board three-cylinder 1.3-liter turbo-diesel is only used to charge the car's lithium-ion battery pack. The batteries may also be charged by a standard household current in about three hours.

Running on just electricity, the Flextreme is capable of driving up to 34 miles before the diesel engine fires up to pour juice back into the batteries. This range, GM claims, will enable many drivers to own the vehicle for months or years without ever traveling far enough to require the Flextreme's diesel engine to run during their normal commute, providing completely emissions-free operation.

Super low aerodynamics play a huge role in achieving greater driving range on electric-only power. According to GM, aero is even more important than weight, so the Flextreme features many design touches that improve its aerodynamic drag coefficient (Cd).

The base of the hood is pushed way forward, conventional stick-out rear-view mirrors are replaced by flush-mounted rear-view cameras, there are no exposed door handles, and the trailing edge of the roof remains high. Each of these design elements help smooth the flow of air over the car, making it easier for the electric motor to do its job. While the wheels look to have conventional spokes, the wheel face doesn't create energy-robbing turbulence, another mpg-increasing touch.

Flextreme features "FlexDoors" and "FlexLoad" systems. The FlexDoors feature conventionally opening front doors with reverse opening rears. There is no conventional B-pillar -- something Saturn has used for years on its old Ion Coupe.

The FlexLoad system is more unusual, and consists of an electrically powered load floor that literally hands you your stowed luggage. In keeping with the electrically-powered theme of this concept, the Flextreme carries twin Segway scooters in its cargo compartment.

The Saturn Flextreme shows that GM has taken yet another step toward production for their eFlex family of vehicles. You could be driving electric before you know it. E-mail to a friend

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