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Comment by bee_rider | Hacker News Reader

Or I could be pessimistic about GPS -- these things are, albeit in limited numbers, on the road and actually being used by customers, right? I guess I'm surprised GPS is so reliable that this isn't a widespread, constant issue, if this is the normal "I lost GPS" behavior.

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It could be a middle ground kind of thing. The cars have to trust something. For position you have GPS + some interpolation based on your movement sensors + some buildings/streets and maps (also unreliable since construction etc changes a lot, a lot of buildings and intersections look the same, etc).

Computers are very far away from understanding where they are from context alone. Hell most humans don't know where they are. So if you have a short GPS outage they will be able to continue navigating due to other sensors, but the longer the GPS outage/issues persist the more unlikely it is that they still know where they are.

There should definitely be a safety to drive to the side of the road and wait though.

Dead reckoning works surprisingly well at least in Teslas, of which the precision can be seen when they move around in underground facilities and finally resurface: the car pops up pretty close to the entry point.

In any case, aren't all self-driving vehicles equipped with lidars and work in pre-mapped regions? I would 100% expect they are able to just use those maps with lidar to precisely geolocate themselves, probably more precisely than with GPS. And, indeed, GPS itself can at times be inaccurate or simply not available due to obstructions.

So what I'm saying, maybe it's wasn't the GPS.

> aren't all self-driving vehicles equipped with lidars

I believe Tesla has made a lot of noise about not using lidar.[0]

[0]: https://venturebeat.com/2021/07/03/tesla-ai-chief-explains-w...

In this context Tesla is not an example of a self-driving car I think, what was discussed was robo-taxis and I think all of them have lidar

Maybe at some point in the future, but Teslas aren't self-driving vehicles: you always need a driver in them, even (or maybe even: more so) in the case of FSD Beta.

I imagine these robotaxi vehicles would not have stayed on the road had they have had a safety driver in them :).

Yeah, I sort of expected a lizard brain/mammal brain split: features like object avoidance and the ability to pull over don't require the car to know where on Earth it is, and if the car can't identify to side of the road and drive to it safely with local sensors, then it just isn't fit to be on the road. That sort of stuff needs to be operate with an antilock-breaking/"fire the airbags?" level of reliability.

"Where on Earth am I" on the other hand is basically irrelevant to safety. Run it on the entertainment console or whatever. Interpolate position, come up with heuristics, whatever. I mean, it should be like two reasonably competent people on a road-trip -- if you are the driver and I'm the map guy, you aren't going to just stomp on the brakes when I inevitable lose track of where we are (I'm bad at navigating). You'd probably just go along the road while I worked it out, unless I was really confused, in which case you'd presumably pull over somewhere.

Obviously there is no failsafe that pulls the car over, otherwise you would see that the cars had pulled over. This might be annoying on city streets but imagine if it were on the highway. An almost guaranteed 50 car pileup. If history is any guide, this will actually happen in the next few years and be followed by a lawsuit and regulation.

That's assuming that there's a space to pull over, which is often not the case on city streets. Especially, when every AV wants to pull over.

Stopping as close to a curb as possible is still better than stopping in the middle of the line. And much better than stopping on an intersection.

I mean, if we were driving together -- you have the steering wheel, I have the map -- and I say "woah I have no idea where we are," what would you do? I guess you would just drive around until I figured it out, or found a safe spot to pull over...

Also the assumption that the fail-safe _works_. Any of these fail-safes are much more complex than a classical fail-safe.

Could it be GPS spoofing that is causing this then?

Malice, incompetence, all that jazz...

Still. I would expect some kind of sanity check so that they aren't stopping in the middle of the road.

If local sensors tell you the road is blocked, fine. But if remote data tells you one thing, and local sensors tell you something else, the fail safe should be pulling over to the side of the road.

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