Part of the idea is that when in heavy traffic the computer would take over. So one could in theory focus on something more productive, even getting work done. How far awary are we from seeing people in the drivers seat with their laptops open instead of focusing on the road? The argument could be made that computers take over for pilots on planes so this can work. However, if someone were to modify the software or even over wireless connections take over the computer it could lead to chaos.
The system is based around LIDAR (laser) and cameras. If the system were to be active and the laser beam was to be disrupted, modified, or impeded it could alter where the computer thinks other cars are.
Audi's system is currently limited to 37 miles per hour and high traffic situations. The 2016 Audi A8 would be potentially the first vehicle to be available with it.