Mhhh....well.....believe it or not I enjoy driving a lot therefore I wouldn't really be happy if the car drove itself and I ended as a spectator.
However you shouldn't forget that these improvements wont suddenly appear in one car. They'll do every thing step by step and make sure it works fine....or at least I would hope so.
But I don't think that relying on a computer is such a big concern. The example of the airplane is a very good one. If you take a look at today's airplanes, what the pilot really does is feed some info into the compu and the plane more or less flies by itself. If you take a closer look at the way we live nowadays we depend on computers a lot and most of the time they don't make mistakes. If a system like the one you're saying should appear...I don't think that computer reliabilitie would be a big concern....that is unless it runs on Windows or any other microsoft product
(bad joke...I know). I find a problem with a sensor or something like that to be a bigger concern....but no so big as it would surely have backup systems.
However (and I'm thinking "start wars" on this one)...should such a system be implemented it would also require a complete change in the road infrastructure. Your junction concern is a perfect example. You just can't build such a system into our current roads. However....if it was implemented on current roads my guess would be that the system would only work on highways and other roads where obstacles like pedestrians are no concern and in ihabited zones and such then the driver would have some kind of control over the vehicle. Mhh....I guess that you could say that it would be more or less like a modern plane. The pilot executes the take off and the landing but the plane does the rest.
But the only true thing is that such a system is still so far away that it's just as probable that we'll be driving flying cars before such a system is implemented. However some parts of that system could be used and in fact they are. If I'm not mistaken the Mercedes S class has a function in the cruise control that always keeps a safe distance with the car in front regardless of weather the driver brakes or not. Trucks that travel one behind the other and are only separated by inches, and therefore needing less space and increasing aerodynamic efficiency, are just a few years away from the real roads. But if you take a look...all these systems still depend somewhat on the driver.
I think it will still be a long time before the driver becomes a passanger. Fortunately for the very few of us that find driving to be relaxing.