Google's LIDAR can see approximately 60 meters out. At 70mph, this gives the autonomous car under 2 seconds to perceive the problem and stop.

Most humans have a perception-reaction time of approximately 2.5-3.0 seconds on a highway, so the human range drops to 2-7 seconds. Factor in the time it takes to apply a maneuver (move foot to break pedal, apply break) and it drops even further -- I'm not certain by how much -- likely another 1-2 seconds. At your lower bound of 0.1 miles, I think the autonomous car already has the advantage.

I think it's clear that a computer would react and apply a maneuver tremendously faster than a human. I also think it's obvious that to have a clear advantage over a human on a highway, these sensors need additional range. From what I understand, Google is working on their own LIDAR sensor (an upgrade from the Velodyne they use now), so perhaps they also have this in mind.

I'd love to see more data on this stuff.