Under what circumstances is Collision Avoidance expected to -- or not expected to -- avoid a collision? I was driving in low-speed stop-and-go traffic this morning and was momentarily distracted when the pickup in front of me stopped. Before I saw him and could stop I bumped into the back of him and his trailer hitch put a significant dent in the plastic "nose cone" of my car (fortunately, absolutely no damage to his vehicle). It is bad enough that a Model S has effectively no front bumper, but I guess I kind of expected Collision Avoidance to slam on the brakes before hitting the car in front of me. Unreasonable/unrealistic?