Cruise offers something unique in that it is an aftermarket option to convert any car (initial launch is limited to 2012 or later Audi A4/S4 and will only work on California highways) into a self-driving car. They are initially offering the product to 50 people who are willing to spend $10,000 for the aftermarket option, and they plan to install them in early 2015.
Unlike the Audi A7 Autonomous, this aftermarket option is not so hidden within the vehicle, but still smaller than the Google self-driving car’s current equipment. Cameras and radar are in a device attached to the roof, connected to a small computer in the trunk. The equipment will control the steering, acceleration, and braking. Similar to the A7 Autonomous, it seems like it takes an advanced adaptive cruise control and combines it with advanced lane maintenance steering.
At this point, they have only mapped the highways in the San Francisco Bay Area, but they plan to download additional roads as the information is available.
I look forward to hearing more reviews of the actual release version, and see how it compares with the other self-driving implementations. As it will be available in 2015, it seems to be the most advanced self-driving option available. It will be interesting to see how well the technology can be implemented in other cars and how soon it will be expanded beyond the San Francisco area.