I'll bet that in the near future (next decade or so), there will be rising incidents of traffic being blocked due to a stopped automated car who's driver is not responsive, but the computer couldn't handle some construction or weather, and went into fail-safe mode, simply slowing down and stopping (but not pulling over due to lack of space).
Heck, we're halfway there with people checking FB on their phones at stoplights, so anticipating this seems reasonable. We haven't solved that problem, and I don't think we'll solve the one you raise (not for a much longer time, at least). Valid problem, but a solution is likely far off.