I was driving across the east side of SF and hit a patch of lights that were out.

The Waymo's were just going really slow through the intersection. It seemed that the "light is out means 4-way stop" dynamic caused them to go into ultra-timid mode. And of course the human drivers did the typical slow and roll, with decent interleaving.

The result was that each Waymo took about 4x as long to get through the intersections. I saw one Waymo get bluffed out of its driving slot by cross traffic for perhaps 8 slots.

This was coupled with the fact that the Waymos seemed to all be following the same route. I saw a line of about a dozen trying to turn left, which is the trickiest thing to navigate.

And of course I saw one driver get pissed off and drive around a Waymo that was advancing slowly, with the predictable result that the Waymo stopped and lost three more slots through the intersection.

On normal days, Waymos are much better at the 4-way stops than they used to be a few years back, by which I mean they are no longer dangerously timid. The Zoox (Amazon) cars are more like the Waymos used to be.

I expect there will be some software tweaks that will improve this situation, both routing around self-induced congestion and reading and crossing streets with dead lights.

Note that I didn't see any actually dead Waymos as others have reported here. I believe this is an extreme failsafe mode, and perhaps related to just too much weirdness for the software to handle.

It would be interesting to see the internal post mortem.

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smugma 2 hours ago | parent | next [-]

Failed pretty badly but no reported injuries or even accidents so not that badly.

And if you’re Waymo, it’s a short-term reputation hit but great experience to learn from and improve.

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markus_zhang 2 hours ago | parent | prev | next [-]

I’m curious what’s the regulation in this scenario? In Canada I think light off means 4-way stop signs so everyone obeys that, or at least most of everyone. What’s the situation in SF?

	▲	cjsplat an hour ago \| parent \| next [-]
		Yes, that is the same law in California, but so many people drift through stop signs that the guidance is close to meaningless. In addition, there are 4-way stop signs all over SF and tourists regularly comment on how they work here. The law is clear - yield to the right, but that is a pretty slow system in congested roads. The local custom in SF is that someone is usually obviously first, rightmost, or just most aggressive, and opposing pairs of cars go simultaneously, while being wary about left turns. Of course pedestrians have right of way in California, so someone in a crosswalk gives implied right of way to the road parallel to the person's crosswalk. The result is 2x or better throughput, and lots of confused tourists. So ... with the lights out on a Saturday before Xmas, there was a mess of SF local driving protocol, irritated shoppers, people coming to SF for Xmas parties, and just normal Saturday car and foot traffic. I thought Waymo did pretty well, but as I said, I didn't see any ones that were dead in the middle of the street..
	▲	khuey an hour ago \| parent \| prev [-]
		Legally in the United States a completely dead traffic signal becomes an all way stop.

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suzzer99 2 hours ago | parent | prev [-]

I got stuck behind a Zoox in SF trying to cross the street from an alley. There was an endless stream of stop & go traffic and the Zoox refused to push itself into traffic, despite other cars deliberately giving it space. I wasn't sure if honking at it would help or hurt the situation.