Robo cards are reactive. The can operate in an environment where 99.9% of the other vehicles have an intelligent( hopeful semi intelligent anyway) person behind the wheel. In an all robo car environment my guess is that they will feed back loop themselves into a standstill.
Yes, and through their telematics, automated cars will not do some of the dumb things a human driver will attempt, such as running a red light or passing when it is unsafe to do so. Think of riding on an attraction at Disney World vs. how driving is done today. It will also vastly improve safety with older drivers and make accidents caused by drunk drivers a thing of the past.