It definitely does not respond to flashing headlights in that manner. You’re observing its default behavior when at a 4 way stop with other vehicles not moving.
You're right I don't have inside information, but we've been interacting with them on the street for years in SF. Waymos don't wait for human subjective guidance to give them clearance to pass, as evidenced by tons of videos and IRL experience. As soon as they come to a required stop, and if a vehicle or other object's linear travel path does not intersect it, it will go. Flashing lights will not change this behavior. (Yes you're right there is a regulatory requirement to respond to safety officer guidance, but compliance is spotty as evidenced by a lot of videos of vehicles entering active crime zones, etc.)
Unlike the traffic cops directing traffic that would likely require special programming, "proceed if the other car flashes its lights at you" is completely the kind of thing that could just accidentally fall out of a neural network learning to imitate humans.
Hopefully if they ever go to Sri Lanka they get localised tuning because I was surprised to find out flashing your lights over there doesn't mean "go ahead", it means "if you don't get out of my way I will ram you"
And then there's trucks flashing an indicator to say it's safe to overtake if you're behind them. In the UK it's the nearside indicator, which makes sense: it's a bit like the truck is pulling over to let you pass. In Aotearo, it's often the off-side indicator, so you think the truck is going to pull out in front of you. I've never understood what the Aotearoa drivers are thinking there
It also doesn't make sense because "get out of my way or I will ram you" is the default state of operating a motor vehicle. Not the goal but the physical reality of it.
I think we're not interpreting the original comment in the same way.
In most places, I think, when driving on the highway, flashing your lights when behind someone means basically 'I would like to overtake you'. Same here in the UK. But that's very specific to that context. You would never see a 'go ahead' context that would mean 'get out of my way', right?
But what the original comment means is there are some countries where you'd think it was 'go ahead' but it really means 'get out of the way'. Like if you're both on a main road, and you are signaling to turn into a side road, the opposing car flashes the lights and that means you can turn. I assume the same in Serbia.
But in some places that can actually mean don't turn, I'm going first. Which I think is what the parent is describing.
You are right that I did not read it the same way, and yes, the unwritten rules are matching in Serbia. FWIW, I've mostly switched to using left-turn signal to indicate "I'd like to overtake", which I've seen done on EU highways.
Waymo has published a ton about the imitation learning they've been using since 2018. They're not imitating random cars but their drivers who are paid to drive around and follow traffic laws.
It's not enough so they use heavy reinforcement learning etc. but it's still a huge foundation to build on.
Waymo immitates humans insofar as its neural net trained on avoiding collisions after millions of miles of video footage and LIDAR data on roads shared with humans causes it to immitate humans.
It's likely manually programmed not to (incorrectly) turn the wheel to the left while stopped and waiting for an opportunity to turn. If you get rear-ended, you'll end up in the lane of oncoming traffic. It's certainly programmed to use its turn signals to indicate when it is going to turn. But after driving around thousands of cars without turn signals on but with their wheels pointed left, it "knows" to predict that they're about to turn, and might immitate humans by anticipating that action and moving to pass the stopped car on the right.
