Among the sedan models, Mercedes-Benz will also offer the E250 diesel, the E350, and the E550. The E400 Hybrid will be the second most powerful. The list of driver assistance features, relying on a stereoscopic camera system and millimeter wave radar, is extensive. Both adaptive cruise control and lane-keeping assist combine to, as Mercedes-Benz says, "semi-autonomously follow in-line traffic." Mercedes-Benz offered few details of this system, but has previously talked about a system designed to drive the car in heavy traffic. The system in the E-class probably only works up to a certain speed, and may require the driver to keep a hand on the wheel.