Audi's electronics division has developed a trailer-backing assistant function for the next-generation European Q7 due as a 2015 model. It is not scheduled for the U.S. market. The system pairs a sensor on the tow ball that is electronically linked to the steering system by the MMI (multimedia interface). Engage reverse and use the MMI knob to direct the trailer where you want it to go -- by watching the mirrors, rear camera, or looking out the window -- and the car will do the steering for you. It's said to adapt to trailers of different sizes automatically and will not turn so tightly as to jackknife the trailer. We hope the feature will spread to other SUVs and perhaps smaller pickups.