At 30 miles per hour, the majority of the stopping distance is reaction time from a human. Self-driving cars have maybe 10/20 of that reaction time in the case of immanent collision. I also don't know about you, but my car can stop in significantly less than pretty much all of the stated distances by a fraction.
at 30mph breaking is about 50/50 perception time and breaking time for a total of 3-4s. Self-driving cars would an improvement for sure, they would have a max 2 second emergency break, but not quick enough as far as I understand. Even if that were enough, I would not appreciate my cab emergency breaking randomly because a kid steps out in front of a bus. Its best to slowly stop, then slowly accelerate. Maybe the optimal solution is to creep past the buss?
