Comment by scarmig 3 days ago
It depends on the situation, and we need more data/video. But if there are a bunch of children milling about an elementary school in a chaotic situation with lots of double parking, 17 mph is too fast, and the Waymo should have been driving more conservatively.
Many states in the US have the Basic Speed Law, e.g. California:
> No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or property.
The speed limit isn't supposed to be a carte blanche to drive at that speed no matter what; the basic speed law is supposed to "win." In practice, enforcement is a lot more clear cut at the posted speed limit and officers don't want to write tickets that are hard to argue in court.
That law seems more likely to assign blame to drivers if they hit someone. So practically it's not enforced but in accidents it becomes a justification for assigning fault.
I mean yeah. If you were traveling at some speed and caused damage to persons or property, that's reasonable, but refutable, evidence that you were traveling at a speed that endangered persons or property.
And at the same time, if you were traveling at some speed and no damage was caused, it's harder to say that persons or property were endangered.
Exactly. That’s why I’ve always said the driving is a truly AGI requiring activity. It’s not just about sensors and speed limits and feedback loops. It’s about having a true understanding for everything that’s happening around you:
Having an understanding for the density and make up of an obstacle that blew in front of you, because it was just a cardboard box. Seeing how it tumbles lightly through the wind, and forming a complete model of its mass and structure in your mind instantaneously. Recognizing that that flimsy fragment though large will do no damage and doesn’t justify a swerve.
Getting in the mind of a car in front of you, by seeing subtle hints of where the driver is looking down, and recognizing that they’re not fully paying attention. Seeing them sort of inch over because you can tell they want to change lanes, but they’re not quite there yet.
Or in this case, perhaps hearing the sounds of children playing, recognizing that it’s 3:20 PM, and that school is out, other cars, double parked as you mentioned, all screaming instantly to a human driver to be extremely cautious and kids could be jumping out from anywhere.
humans aren't even a general intelligence at these requirements.
> How many human drivers do you think would pass the bar you're setting?
How many humans drivers would pass it, and what proportion of the time? Even the best drivers do not constantly maintain peak vigilance, because they are human.
> IMO, the bar should be that the technology is a significant improvement over the average performance of human drivers (which I don't think is that hard), not necessarily perfect.
In practice, this isn't reasonable, because "hey we're slightly better than a population that includes the drunks, the inattentive, and the infirm" is not going to win public trust. And, of course, a system that is barely better than average humans might worsen safety, if it ends up replacing driving by those who would normally drive especially safe.
I think "better than the average performance of a 75th or 90th percentile human driver" might be a good way to look at things.
It's going to be a weird thing, because odds are the distribution of accidents that do happen won't look much like human ones. It will have superhuman saves (like that scooter one), but it will also crash in situations that we can't really picture humans doing.
I'm reminded of airbags; even first generation airbags made things much safer overall, but they occasionally decapitated a short person or child in a 5MPH parking lot fender bender. This was hard for the public to stomach, and if it's your kid who is internally decapitated by the airbag in a small accident, I don't think you'll really accept "it's safer on average to have an airbag!"
The parent comment said the bar should be "significant improvement" over the average performance of human drivers.
Then you said, "this isn't reasonable", and the bar shouldn't be "slightly better" or "barely better". It should be at least better than the 75th percentile driver.
It sounds like you either misread the parent comment or you're phrasing your response as disagreement despite proposing roughly the same thing as the parent comment.
All depends on what you read as "significant improvement".
A 20% lower fatal crash rate compared to the average might be a significant improvement-- from a public health standpoint, this is huge if you could reduce traffic deaths by 20%.
But if you don't get the worst drivers to replace their driving with autonomous, that "20% less than average" might actually make things worse. That's my point. The bar has to be pretty dang high to be sure that you will actually make things better.
> In practice, this isn't reasonable, because "hey we're slightly better than a population that includes the drunks, the inattentive, and the infirm" is not going to win public trust.
Sadly, you're right, but as rational people, we can acknowledge that it should. I care about reducing injuries and deaths, and the %tile of human performance needed for that is probably something like 30%ile. It's definitely well below 75%ile.
> But if there are a bunch of children milling about an elementary school in a chaotic situation with lots of double parking, 17 mph is too fast
Hey, I'd agree with this-- and it's worth noting that 17^2 - 5^2 > 16^2, so even 1MPH slower would likely have resulted in no contact in this scenario.
But, I'd say the majority of the time it's OK to pass an elementary school at 20-25MPH. Anything carries a certain level of risk, of course. So we really need to know more about the situation to judge the Waymo's speed. I will say that generally Waymo seems to be on the conservative end in the scenarios I've seen.
(My back of napkin math says an attentive human driver going at 12MPH would hit the pedestrian at the same speed if what we've been told is accurate).
The schools I'm thinking of have sidewalks with some degree of protection/offset from street, and the crossings are protected by human crossing guards during times when students are going to schools. The posted limits are "25 (MPH) When Children Are Present" and traffic generally moves at 20MPH during most of those times.
There are definitely times and situation where the right speed is 7MPH and even that feels "fast", though, too.
> Hey, I'd agree with this-- and it's worth noting that 17^2 - 5^2 > 16^2, so even 1MPH slower would likely have resulted in no contact in this scenario.
Only with instant reaction time and linear deceleration.
Neither of those are the case. It takes time for even a Waymo to recognize a dangerous situation and apply the brake and deceleration of vehicles is not actually linear.
> It takes time for even a Waymo to recognize a dangerous situation
Reaction time makes the math even better here. You travel v1 * reaction_time no matter what, before entering the deceleration regime. So if v1 gets smaller, you get to spend a greater proportion of time in the deceleration regime.
> linear deceleration.
After reaction time, stopping distance is pretty close to n^2. There's weird effects at high speed (contribution from drag) and at very low speed, but they have pretty modest contributions.
I think the strategy is a lot more nuanced than that.
In any case, with zero reaction time, linear deceleration time to stop is proportional to velocity squared. With reaction time, the linear deceleration time is that plus the velocity times the reaction time.
so the two cases we're comparing are 17 * r + (17^2 - 5^2) vs. 16 * r + (16^2), or 17 * r + 264 vs 16 * r + 256. As long as reaction time isn't negative, a vehicle that could slow to 5MPH starting at 17MPH could slow to 0MPH starting at 16MPH.
(There are weird things that happen at <2.5MPH reducing deceleration to sublinear, but the car moves only a few inches at these speeds during a panic stop).
Pretty common at airports; of course, the `parking` only lasts a few minutes at most.
More like standing, and quite common in a school zone.
I would not race at 17 MPH through such an area. Of course, Waymo will find a way to describe themselves as the heroes of this situation.
> But if there are a bunch of children milling about an elementary school in a chaotic situation with lots of double parking, 17 mph is too fast, and the Waymo should have been driving more conservatively.
UK driving theory test has a part called Hazard Perception: not reacting on children milling around would be considered a fail.
[0] https://www.safedrivingforlife.info/free-practice-tests/haza...