Quadrasteer is no longer available on 2WD models, standard wheel sizes have been bumped up to 17 inches, and on extended and crew cab models; a power sunroof that includes HomeLink and a deluxe overhead console are new options. Chevy takes a step backward this year with the return of rear drum brakes, as opposed to last year's four-wheel disc setup. A gasoline/electric hybrid model is also introduced in limited quantities this year. Basically a "mild" hybrid, the system provides no power boost, but does allow for automatic engine startup and shutdown at stops. This truck also comes with four 120-volt AC power outlets and is the only Silverado with rear disc brakes this year. The hybrid truck is only available in Western states and Florida.