The Lexus RX 450h can operate using only electric, only gasoline, or use both in tandem. The 350 uses a conventional 6-speed transmission, but the Lexus RX 450h utilizes a continuously variable transmission.
TheLexus RX 450h hybrid system includes a 288-volt battery pack that sits under the rear seat, which sends power to the front mounted motor-generator that drives the front wheels. In all-wheel drive trims, another motor-generator drives the rear wheels. Both models have another generator that's engine-driven rather than battery-driven, so it functions as a starter and can power the battery pack or other electric motors.
Lexus uses a handling system it calls Vehicle Dynamics Integrated Management (VDIM); it's standard on the Lexus RX 450h and optional on the 350. If the system detects a loss of control, it uses all the electronic systems -- ABS, brake assist, traction control, and stability control -- as well as throttle control to help the RX get back on track. In the 450h, the electronically controlled brakes work with VDIM as well.
