GM announced today that its all-new LaCrosse will get 30 mpg on the highway thanks to the direct-injection four-cylinder from the Chevy Equinox and GMC Terrain.

But that means the buyers of other Buick vehicles -- the current LaCrosse and the Lucerne larger sedan -- are getting even older. The median age rose to 68 from 67 in 2006, according to GM.