A midsize sport sedan that is relatively unchanged this year, the 2009 Lexus GS 450h is powered by a gas-electric hybrid system. The sophisticated hybrid system combines a 3.5L V6 gas engine with a high-output electric motor, which together generate a total of 340 hp and the 450 refers to the hybrid's output as being equivalent to a 4.5L V8 engine. The electric motor supplements the gas engine during start-up and offers additional power under heavy acceleration, recharging itself using a process called regenerative braking. The GS 450h features an electronically controlled continuously variable transmission (CVT) with normal, snow and sport modes. A fast and powerful car, the 450h can take 0-60 mph in 5.2 seconds. Lexus GS 450h standard safety equipment features stability and traction control, antilock brake system, emergency brake assist and every airbag under the sun, including dual-front knee bags and side-curtain bags, among others. EPA-estimated fuel economy rates 22 mpg city/25 mpg hwy and 23 mpg in combined driving.