The 2012 Buick Regal comes in four styles: the Regal luxury sports sedan, the new Regal with eAssist, the Regal Turbo and a sporty new GS model. The eAssist and the GS are all new, with each one offering specific driving experiences.

Our test vehicle was the Regal with eAssist. The main takeaway we had on the driving experience of this vehicle was that the experience lasted longer between fill-ups. Rated at 25 miles per gallon in the city and 36 mpg on the road, the Regal eAssist uses a battery to power the vehicle’s systems during auto stops at red lights, and also to provide a boost during heavy acceleration. Like the eAssist system in the all-new 2013 Chevy Malibu, eAssist is not technically a hybrid, according to GM.

The Regal’s 2.4-liter Ecotec 4-cylinder engine is hooked to a 6-speed automatic transmission. The eAssist system uses energy stored in a lithium-ion battery to provide a boost in heavy acceleration and to power the car’s electrical systems when the auto-stop feature kills the engine during stops.

In both the Malibu and Regal, GM has fine-tuned the auto-stop feature to make the engine stop and start almost imperceptible.

The new GS model is the sport cousin to the base Regal, which delivers 19 mpg in the city and 31 mpg on the highway. The GS cranks out a turbocharged 270 horses and 295 lb.-ft. of torque for a much sportier performance. But if saving gasoline is what you have in mind, the eAssist system delivers the goods.

The cabin has lots of upscale features, including dual zone air, heated leather seats, remote keyless entry, a CD and MP3 player with speed-sensitive volume, USB, Bluetooth and Sirius Satellite Radio. Three premium packages are available that upgrade the interior significantly with things like parking assist, seat adjustability, automatic HID headlights, upgraded Harman/kardon sound and upgraded wheels.

Our test Regal eAssist had the Premium II group plus navigation, which I found to be one of the better nav systems available. The 7-inch display was crisp and clear, and the streets were actually updated to include roads not shown in most other systems. I did find that the center armrest and console in the Regal are oddly-shaped to accommodate two drink holders, but overall the interior is very nice. The seats are firm and comfortable on extended drives.

On the road, the Regal eAssist doesn’t bolt from a stop, but don’t forget about that whole 36 estimated mpg on the highway thing. Interstate merging power was sufficient, and the car felt planted in hard turns. Braking was very good.

The 2012 Regal eAssist has not yet been tested by the government for safety, but the 2011 model was a “Top Safety Pick” from the Insurance Institute for Highway Safety.

The vehicle has standard anti-lock brakes, stability and traction control systems, a full complement of airbags and daytime running lights.

Engine

2.4-liter Ecotec 4-cylinder

with eAssist

Transmission

6-speed automatic

Horsepower

182

Test model base price

$29,515

As tested price

$34,470

EPA mileage rating

25 mpg city / 36 mpg highway