[AlexandrB]

Even without seeing other people's faces, you start to notice car "body language". For example, a car that is sticking close to a lane divider is probably about to try to change lanes. I always wondered to what extent (if any) self-driving AI tries to take this into account and whether, even legal, maneuvers by self-driving AI might be surprising to other drivers looking for these kinds of subtle signals.

[AlotOfReading]

It's incorporated into autonomous vehicles in a few different ways (mainly through ML), but current state of the art isn't perfect. Humans are probably still better at reading those subtle patterns earlier.

[wpietri]

Is it incorporated both ways? That is, are autonomous vehicles trained to express intention through subtle movements?

[jlund-molfese]

Isn’t that what turn signals are for? Car body language is somewhat location-dependent. Rural Missouri has more cautious drivers and downtown NYC more aggressive drivers. Seems complicated to modify the car’s behavior at such a fine level, but perhaps it’ll happen once the bigger issues are worked out. On-board, personalized learning from your commute would be a neat selling point.

[wpietri]

Yes, social signals are location dependent. But driving in traffic is a social activity. And ignoring that strikes me as a big issue indeed.

[kbrkbr]

Even the enforcement of rules and the expectation on that are location dependent. Someone I know walked on a crosswalk in a southern european country, expecting that this will be honored like it is here. Ended up in hospital for two weeks. No driver there expected it.

[r00fus]

Having driven in the SF Bay with waymo and cruise vehicles - they definitely do signal a sort of extremely hesitant/cautious "body language".

Slowing to a stop in an otherwise clear lane because it's cautious around shadows; Always ceding the initiative on 4-way stops, etc.

It's like there's a (diligent but overly cautious) student driver behind the wheel.

[AlotOfReading]

AVs can seem to do that, but it's unintentional. I've never seen or heard anyone describe encoding intent with microbehaviors. The general preference is to make driving intentions as obvious as possible because some people don't pick up on subtleties and we still want to drive safely around them.

[wpietri]

Safety is an important base. But driving in traffic is a collaborative activity, so communication can't just be one way.

[AlotOfReading]

The vehicles are intended to be very predictable for other drivers. I don't consider that to be synonymous with encoding intent into subtle microbehaviors. Instead it means straightforward behaviors like turn signals, appropriate speeds, avoiding last minute lane changes, etc.

[wpietri]

One of the big ways people predict what cars are going to do is by reading intent through both macro- and micro-behaviors. Reading motion intent through subtle motion indicators is not just part of driving; it's something that happens all the time, and not just for humans. Automated vehicles are entering into an environment where that's the case, and that will not change.