Tesla owners say they are wowed -- and alarmed -- by 'full self-driving'

Washington, DC (CNN)Drivers with Tesla's "full self-driving" software often don't know what their cars will do next. Tesla owners have been wowed by their cars' new abilities, but some say they have also been alarmed and frustrated by the accompanying flaws. One second drivers find themselves praising the cars' skills; the next moment they're grabbing the wheel to avoid crashing or breaking the law. "Full self-driving" is a suite of driver-assist features that Tesla hopes can one day enable cars to drive themselves. Other automakers like Mercedes-Benz, GM, Ford and Volvo offer cars with similar features that may change lanes, parallel park, identify speed limit signs and brake for pedestrians.