If you want a preview of how vehicles will change under the new fuel economy rules, look at two sedans arriving this year: the redesigned Hyundai Sonata and the new Buick Regal.
The mid-sized 2011 Sonata, which went on sale last month, is 131 pounds lighter than the previous generation. Hyundai won't offer an optional V-6 engine, says John Krafcik, CEO of Hyundai Motor America.
"Everybody knows that mid-sized sedans are supposed to have a four-cylinder base engine and an optional V-6, right?" Krafcik says. "We say no, there's no need for a V-6 in a mid-sized car anymore -- that's ridiculous.
"It's clear that by 2016 you won't find a V-6 in a mid-sized car. I guarantee it, other than perhaps a few specialty vehicles or low-volume vehicles."
The engine in all Sonatas is a 2.4-liter inline four-cylinder with gasoline direct injection, rated at 198 hp. The weight of the base GLS model with manual transmission dropped from 3,292 pounds to 3,161 pounds.