With discussions of raising gas-mileage standards beyond the 34 mpg they'll reach in 2015, there's a lot of shrieking about how we'll all be driving subcompacts if the rules get any tougher.
Consider the 2012 Chevrolet Impala, Chevy's rapidly aging full-sized four-door sedan. Equipped with an engine transplant and soldiering on for another few years in a body first launched for the 2006 model year, the 2012 Impala will be rated at 18 mpg city and a notable 30 mpg highway.
Think of it: A full-size American sedan that consumes no more gas on the highway than the compact cars of just a few years ago.
2012 Chevrolet Impala Leaked
Note that the new engine's power is just a single horsepower below the old Impala SS model, which required a V-8 to produce that power--and was rated just at 16 mpg city, 24 mpg highway.
The 2012 mileage figures are slightly better than the Impala's older V-6 options, but a number of 30 mpg or above definitely gets attention in such a large and powerful car.
Imagine what the Impala could do if fitted with, say, a turbocharged 2.5-liter four with the eAssist mild-hybrid system, in a lighter, more aerodynamic body.
For advances like that, though, we'll have to wait a few more years. The replacement for the current Impala was frozen during GM's bankruptcy crisis, and so we're not likely to see an all-new model until early 2013, as a 2014 model.