Waymo robotaxi hits a child near an elementary school in Santa Monica • Hacker News Board

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#391

Post by estimator7292 » Thu, Jan 29, 2026, 9:31 PM UTC

jjav wrote: post #154

jobs_throwaway wrote: post #8

Earlier quoted context omitted.

Yup. And to add > Waymo said in its blog post that its “peer-reviewed model” shows a “fully attentive human driver in this same situation would have made contact with the pedestrian at approximately 14 mph.” It's likely that a fully-attentive human driver would have done worse. With a distracted driver (a huge portion of human drivers) it could've been catastrophic.

> It's likely that a fully-attentive human driver would have done worse. We'd have to see video of the full scene to have a better judgement, but I wouldn't call it likely. The car reacted quickly once it saw the child. Is that enough? But most humans would have been aware of the big picture scenario much earlier. Are there muliple kids milling around on the sidewalk? Near a school? Is there a big truck/SUV parked th…

It was already moving slowly. 17MPH is pretty conservative. Most human drivers going past my local school are doing at least 30.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#392

Post by danpalmer » Thu, Jan 29, 2026, 9:33 PM UTC

okdood64 wrote: post #370

aanet wrote: post #234

This is the classic Suddenly Revealed Pedestrian test case, which afaik, most NCAP (like EuroNCAP, Japan NCAP) have as part of their standard testing protocols. Having performed this exact test on 3 dozen vehicles (L2/L3/L4) for several AV companies in the Bay Area [1], I would say that Waymo's response, per their blog post [2] has been textbook compliance. (I'm not defending their performance... just their response…

> Waymo will still have to accept some responsibility Why? This is only true if they weren't supposed to be on the road in the first place. Which is not true.

In a technical sense, maybe, but it's all going to be about optics. They have a responsibility to handle the situation well even if it's not their fault, and the public will hold them accountable for what they deem the involvement was, which may not be the actual scenario.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#393

Post by Veserv » Thu, Jan 29, 2026, 9:35 PM UTC

10000truths wrote: post #380

Veserv wrote: post #244

Earlier quoted context omitted.

Err, that is not the desirable statistic you seem to think it is. American drivers average ~3 trillion miles per year [1]. That means ~7000 child pedestrian injurys per year [2] would be ~1 per 430 million miles. Waymo has done on the order of 100-200 million miles autonomously. So this would be ~2-4x more injurys than the human average. However, the child pedestrian injury rate is only a official estimate (it is pos…

I suspect that highway miles heavily skew this statistic. There's naturally far fewer pedestrians on highways (lower numerator), people travel longer distances on highways (higher denominator), and Waymo vehicles didn't drive on highways until recently. If you look only at non-highway miles, you'll get a much more accurate comparison.

Then you or Waymo can meet the burden of proof and present that more precise and better information. There is little reason to assume against safety at this point in time except as a intellectual exercise for how more accurate information could be found.

Until then, it is only prudent to defer snap judgements, but increase caution, insist on rigor and transparency, and demand more accurate information.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#394

Post by jjav » Thu, Jan 29, 2026, 9:36 PM UTC

dekhn wrote: post #331

jjav wrote: post #154

Earlier quoted context omitted.

> It's likely that a fully-attentive human driver would have done worse. We'd have to see video of the full scene to have a better judgement, but I wouldn't call it likely. The car reacted quickly once it saw the child. Is that enough? But most humans would have been aware of the big picture scenario much earlier. Are there muliple kids milling around on the sidewalk? Near a school? Is there a big truck/SUV parked th…

In this situation, the car was already driving under the legal speed required for a school zone (25mph when children are present) [edit: some comments in the post suggest there is a 15mph sign, which is sometimes posted; to me, driving 17mph in a 15mph zone is acceptable). I think any fair evaluation of this (once the data was available) would conclude that Waymo was taking reasonable precautions.

> was already driving under the legal speed

That's exactly part of the problem. If it is programmed to be over-cautious and go 17 in a 25 zone, that feels like it is safe. Is it?

It takes human judgment of the entire big picture to say meaningfully whether that is too slow or too fast. Taking the speed limit literally is too rigid, something a computer would do.

Need to take into account the flow of the kids (all walking in line vs. milling around going in all directions), their age (younger ones are a lot more likely to randomly run off in an unsafe direction), what are they doing (e.g. just walking, vs. maybe holding a ball that might bounce and make them run off after it), their clustering and so on.

Driving past a high school with groups of kids chatting on the sidewalk, sure 20mph is safe enough. Driving past an elementary school with a mass of kids with toys moving in different directions on the same sidewalk, 17mph is too fast.

And if I'm watching some smaller kids disappear behind a visual obstruction that makes me nervous they might pop up ahead of it on the street, I slow down to a crawl until I can clearly see that won't happen.

None of this context is encoded in the "25mph when children are present" sign, but for most humans it is quite normal context to consider.

But would be great to see video of the Waymo scene to see if any of these factors was present.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#395

Post by mlsu » Thu, Jan 29, 2026, 9:37 PM UTC

BugsJustFindMe wrote: post #2

From the Waymo blog... > the pedestrian suddenly entered the roadway from behind a tall SUV, moving directly into our vehicle's path. Our technology immediately detected the individual as soon as they began to emerge from behind the stopped vehicle. The Waymo Driver braked hard, reducing speed from approximately 17 mph to under 6 mph before contact was made. > Following contact, the pedestrian stood up immediately, w…

An honest account of this situation would place at least some blame on there being a tall SUV blocking visibility.

These giant SUVs really are the worst when it comes to child safety

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#396

Post by lelanthran » Thu, Jan 29, 2026, 9:42 PM UTC

WheatMillington wrote: post #213

coryrc wrote: post #133

Earlier quoted context omitted.

First, it's still the automobile's fault. At least it was already slowed down to 17 mph to start. Remember that viral video of some Australian in a pickup ragdolling a girl across the road? Most every comment is "well he was going the speed limit no fault for him!" No asshole, you hit someone. It's your fault. He got zero charges and the girl was seriously injured.

You seem to be implying that there are no circumstances in which a vehicle can hit a pedestrian and the driver not be at fault... which is absurd.

> You seem to be implying that there are no circumstances in which a vehicle can hit a pedestrian and the driver not be at fault... which is absurd.

It is absurd, but that doesn't mean that the attitude can't be useful!

In teaching my teenager to drive, I drilled into him the fact that, in every accident, regardless of who is "at fault", there is almost always something that the other party could have done to mitigate it. I gave him plenty of situations as examples...

You're going down a street that has kids on the sidewalk? You better be prepared to have one of those kids come out in front of the car while rough-housing, playing, whatever.

You had right of way? Maybe you did, but did you even look at the opposing traffic to see if it was safe to proceed or did you just look at the traffic light?

I've driven, thus far in my life, roughly 600000km (maybe more) with 2x non-trivial accidents, both ruled not my fault. In hindsight, I could have avoided both of them (I was young and not so self-aware).

I'm paranoid when driving, and my stats are much much better than Waymo's (have never injured anyone - even my 2x accidents only had me injured), even though I drive in all sorts of conditions, and on all sorts of roads (many rural, some without markings).

Most people don't drive like this though (although their accident rate is still better than Waymo's).

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#397

Post by moktonar » Thu, Jan 29, 2026, 9:43 PM UTC

The Waymo driver tech is impressive. That said an experienced driver might have recognized the pattern where a stopped big vehicle occludes a part of the road leading to such situation, and might have stopped or slowed down almost to a halt before passing. The Waymo driver reacts faster but is not able to predict such scenarios by filling the gaps, simulating the world to inform decisions. Chapeau to Waymo anyways

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#398

Post by jjav » Thu, Jan 29, 2026, 9:45 PM UTC

jobs_throwaway wrote: post #304

almosthere wrote: post #295

Earlier quoted context omitted.

I don't think it makes sense to lump some drivers better than waymo and worse than waymo. A human brain automatically thinks of all the scenarios, where Waymo has pre-programmed ones (and some NN based ones). So it's scenarios by scenario. Consider this scenario: 5 kids are walking on the sidewalk while you're driving past them. But suddenly a large dumpster is blocking your view of them just as you pass. You saw the…

> A human brain automatically thinks of all the scenarios I don't think this is true. There are infinitely many scenarios in a complex situation like a road with traffic, cars parked, pedestrians about, weather, etc. My brain might be able to quickly assess a handful, but certainly not all.

There aren't infinitely many scenarios to consider, but even if that's a figure of speech, there aren't thousands or even hundreds.

If there's ten kids nearby, that's basically ten path scenarios, and that might be reduced if you have great visibility into some of them.

> My brain might be able to quickly assess a handful, but certainly not all.

What would you do if you can't assess all of them? Just keep driving same speed?

If the situation is too overwhelming you'll almost certainly back off, I know I would. If I'm approaching that school block and there's like 50 small kids running around in all directions, I have no idea what's going on and who is going where, so I'm going to just stop entirely until I can make some sense of it.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#399

Post by recursive » Thu, Jan 29, 2026, 9:45 PM UTC

gruez wrote: post #263

recursive wrote: post #231

Earlier quoted context omitted.

If you clearly define your goals in advance, then you can make success whatever you want. What are Waymo's goals?

Something tells me it wasn't 0 accidents, given that it's impossible.

I guess we'll never know.

Re: Waymo robotaxi hits a child near an elementary school in Santa Monica

#400

Post by AndrewKemendo » Thu, Jan 29, 2026, 9:46 PM UTC

BugsJustFindMe wrote: post #2

From the Waymo blog... > the pedestrian suddenly entered the roadway from behind a tall SUV, moving directly into our vehicle's path. Our technology immediately detected the individual as soon as they began to emerge from behind the stopped vehicle. The Waymo Driver braked hard, reducing speed from approximately 17 mph to under 6 mph before contact was made. > Following contact, the pedestrian stood up immediately, w…

In fact I would call that “superhuman” behavior across the board.

The vast vast vast majority of human drivers would not have been able to accomplish that braking procedure that quickly, and then would not have been able to manage the follow up so quickly.

I have watched other parent drivers in the car pick up line at public schools for the last 16 years and people are absolutely trash at navigating that whole process and parents drive so poorly it’s absurd. At least half parents I see on their phones while literally feet away from hitting some kid.