Correct, although the creep and go after the light is also practiced. Main reason for the Pittsburgh left's popularity is that there are a number of roads in and around the city where during rush hour it's otherwise impossible to ever make a left and have no turn lane.
This happens to me sometimes, my solution is to overshoot by a block, then hook 3 right turns, rather than slow up everyone behind me or pull a daredevil left. I would hope self driving cars would be programmed to follow a strategy like mine while still accommodating daredevils by using cautious acceleration and effective collision avoidance.
In other words, despite the traffic lights not having an official "left turn only" phase, the traffic has naturally created one. I've seen this in China too.
