They can be obscured though, like the car one car ahead of you suddenly braking. With additional radio communication that wouldn't be an issue. Tesla used to brag about the radar being able to bounce under the car in front of you to the car in front of it, but I think stopped talking about that when they removed radar.
> With additional radio communication that wouldn't be an issue.
Given the life and death potential, I consider any signal I get from another car "trust but verify". Having a radio signal about a car a few cars up would maybe get me to slow down but not emergency brake until I had more information.
The hacking potential is just to great.
I always find these discussions funny, we are putting so much time and attention to a problem that is solved: moving many people, multiple locations, in a repeatable way safely, while maximizing for people and speed. They are called trains
Trains don't go to my office. And it wouldn't make sense for them to do so.