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Comment by gilbetron | Hacker News Reader

The prediction talked about here is if you are at a 4-way stop, and the car to your left has it's right turn signal on, you can predict that they are probably turning right, and so it is ok for you to go through the intersection without waiting for them. Currently, and autonomous car will wait until the other car is no longer in the intersection. With prediction, it will act more like a human. That doesn't mean it 100% believes the car will turn right, but will modify its behavior if it sees the car starting to go straight.

Basically, autonomous vehicles almost entirely assume the worst outcome in all situations, and waits until it is safe. So at a 4-way stop, it will wait for all cars to be out of the picture before going, which results in horrendous performance if the intersection is busy.

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When I drive, essentially only use turn signals to restrict my behaviour vs the default assumption. For example, if a car is indicating to turn right, I will assume it is likely to either go right or go straight and wait accordingly.

Reason for this is too many times I've just narrowly avoided a collision because someone forgot to cancel their signal, or they were signalling ridiculously early for a turn they were going to make further up, or even that they just activated the signal accidentally.

Not to suggest prediction is bad, but just that also not treating turn signals with too much authority is safer.

If I am at a 4 way stop and there is a car to my left my prediction is that it's ok for me to go through the intersection regardless of the status of their turn signal because the rules of the road require them to yield to their right. I still pause to observe the trajectory of their vehicle, though, because a lot of people don't seem to know that rule.

I'm not sure if I'm reading your comment correctly, but in case I am...the "yield to the right" rule is only to break a tie if two people arrive at the intersection at the same time. Otherwise, the first to stop is the first to go. I haven't run across many people who don't play by these rules (or maybe my assertive driving style just means everyone else follows my rules anyway).

Well yes, I always yield to vehicles that are already in the intersection, irrespective, again, of their turn signals. Also it is not purely true that "the first to stop is the first to go". Specific minutiae of the law differ depending on region, but generally if I am approaching a 4 way stop with the intent of turning left and another car straight across from me is already stopped and going straight then, while I am waiting for that driver to cross the intersection another vehicle arrives at the stop to my right I am still obligated to yield the intersection to the new car despite having "arrived first". Likewise, when many cars are enqueued at the intersection, turns should continue clockwise, as in most board games, without regard to who is able to zoom up and brake the quickest.

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