Yes, I believe you are agreeing with me. Cars can do that on their own. no central computer needed.
No, if the cars' actions are not coordinated in some way, either by communication with one another or central control, they then know nothing about what other cars are going to do until they do it. With central control or communication, you could have several miles of cars on the freeway, all traveling at 200+ mph, separated by mere inches.
That'll never be done. A blown tire at 200 mph would kill a whole lot of people, as would a teenager throwing a cinder block off an overpass just to see what happens (one of my friends actually had that as a legal case).
Or multiply the kinetic energy of hitting a deer at 65 mph by ten. The debris from the first collision will come flying off, impact the other cars (and possibly oncoming ones), making for a very bad day on the highway.