Lexus again offers its RX 450h crossover models with a choice of front-wheel drive or all-wheel drive. As with the prior RX 400h, which ceased production in 2008, the RX 450h uses a separate rear electric motor-generator to provide power to the rear wheels when road conditions or throttle response dictates. Torque distribution varies depending on driving conditions, and the AWD system is 35 pounds lighter.