Buick is going greener. In a few months, the American automaker plans to introduce the 2012 LaCrosse eAssist. The new green machine is expected to deliver 25 mpg-city/37 mpg-highway. By comparison, the 2011 LaCrosse (with the same 4-cylinder engine) delivered only 19 mpg-city/30 mpg-hwy. Such a rise in mpg can yield an impressive 30 percent gain in fuel economy.

Buick's innovative e-Assist is similar in principal to the belt-alternator-starter (BAS) hybrid-system previously used by other automakers - only much more improved.

The main difference between the original iteration of the BAS system and the newest design featured in the 2012 Buick LaCrosse eAssist is that the latter dispenses three times more power. The eAssist system optimizes fuel economy by "assisting" the gasoline engine, either by shutting down the engine when the car is in an idle position or by cutting off the fuel supply when the car is cruising or decelerating. In either scenario the engine continues to spin, promising a smooth restart.