[argonaut]

Obviously the textual description is limited (e.g. a video would settle this question), but that description alone is hardly unnatural. The behavior of the Google car is behavior I make all the time, and one I see drivers making all the time: inching forwards in the right-hand lane to look at the traffic on the left, then stopping because you've decided not to go for it.

The fact is: slow speed rear ends are really common. I've had them happen to me several times during one year where I commuted every day. I've done it myself on another car.

I would not be surprised if over the course of the next few years Google cars get rear-ended at light to moderate speeds hundreds of times.