The technology is no where near ready yet, but it will get there.
If you look at the problems for the major highways through big cities, a lot of it is caused by ego. People don't merge smoothly, or follow a safe distance, or maintain a constant speed, or even pay enough attention. If your car knows that the car 4 ahead of you is slowing down, and all the cars in between and around know it, everyone can adjust smoothly. No tailgaters. No slow pokes in the fast lane. No unsafe speed. The list is long. When the technology is ready, getting onto a major highway would be like your vehicle becoming part of a large machine until you exit. The traffic flow and safety would both be increased.
I'm keeping an open mind until I see how far along the technology development gets. I can see some major advantages, if they get it right. It will be fascinating to watch it unfold.