4 ms·

I am a little worried that this is still a problem after 20 years. Don't they have simulators to test every weird and unexpected road condition offline? And flo

by grumbel 5mo ago

I am a little worried that this is still a problem after 20 years. Don't they have simulators to test every weird and unexpected road condition offline? And flooded roads aren't exactly an unusual event to begin with.

outside2344 5mo ago
The fact that they aren't a usual event is probably exactly the challenge here.
- antonymoose 5mo ago
  It may not be usual in Atlanta itself, but living on the Southeastern coast within a mile or two of the water, for 30+ years, it’s a surprisingly common occurrence. I’ve got old photos around of kayaking through downtown Charleston during college, for instance, where the street flooding is not only usual but a many times per season occurrence. Lots of seaside areas have the same issue.
  - throwaway2037 5mo ago
    > it’s a surprisingly common occurrence That is wild. What happens to all of the flooded property? Do they tear-down and rebuild everything after every major flood? Or massive rennovations? It cannot believe this is truly possible as flood insurance would become impossible expensive.
- trollbridge 5mo ago
  I’ve lived in a place where it flooded every year or two. It floods regularly where I live now too. Locals know which roads to avoid and not to drive into a flood.
- thrownthatway 5mo ago
  Floods aren’t a usual even. Have you ever even been outside?
- ranger207 5mo ago
  I just moved from an apartment right next to where this Waymo got stuck: https://old.reddit.com/r/Atlanta/comments/1tj00sl/flooding_in_midtown_ooof/ https://old.reddit.com/r/Atlanta/comments/1tj00sl/flooding_i... and I can say that that particular intersection floods about every time it rains hard. That being said, yesterday's rain was particularly heavy and I hadn't seen that intersection flood that bad since before Waymo started being rolled out here
krackers 5mo ago
They can simulate "driving out of a raging fire" but not a flooded street? This seems like an admission that the fancy "world model simulation" doesn't actually mean much https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-frontier-for-autonomous-driving-simulation/ https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-f...
- brookst 5mo ago
  IMO there is a lot of daylight between “is not perfectly capable of simulating all situations and always used perfectly to the full capabilities of the system” and “doesn’t mean much”.
- riknos314 5mo ago
  No simulation is perfect, so ideally you have a feedback look constantly looking at new real-world data as it comes in and finding where the simulation has errors, and updating the simulation to improve the correlation between the simulation and the real world over time. My guess is they did have flooded street sims but the correlation was much lower than expected, or the details of the situation being simulated (lighting, building locations, how dirty the water is, ...) were sufficiently different from the situation that was encountered that the sim based training didn't generalize to the new context.
burnte 5mo ago
In ATL this happens often enough that it's not a shock when it happens, we have lots of drainage problems here. I agree that I would have assumed Waymo had tested in events like this, but clearly not. So what I can say is running in ATL is a great test case for these events, and also the people who live here don't do a better job than Waymo did. There were dozens of people who ruined their cars yesterday trying to drive through deep water.
- QuercusMax 5mo ago
  We had a story in the news this week about a Cybertruck driver who thought his Elonmobile was a boat because it has "wade mode" and deliberately drove into a lake! Humans are very stupid when it comes to driving through standing water!
  - burnte 5mo ago
    I saw that just a day or two before wednesday! Hilarious timing.
  - SR2Z 4mo ago
    To be fair if you take Elon Musk at his word the Cybertruck is supposed to have hermetically sealed powertrain components and be capable of exactly this.
    - mschuster91 4mo ago
      The powertrain is one thing, the more critical issue is the car's structure, including the ventilation system, all sorts of gaps - and also, all hollow spaces, in which you need to balance weep holes (to prevent water condensation and subsequent rusting or weird issues regarding temperature changes) against the ability for external water to end up there at all. Getting that right is a very expensive job and that's why you usually only see true (i.e. no visit to a shop needed afterwards) wade ability on large military vehicles and custom RV builds.
- Muromec 5mo ago
  As much as one could expect waymo to train on it, one could also expect a functioning city to not have flooded streets
marcosdumay 5mo ago
It can just mean that nobody though about flooded streets, what's way more reasonable than it seems because of the birthday paradox. But that also means they need a long time to adapt to a new situation. That may be very bad depending on how fine grained a situation is defined, or it may mean nothing and in a few months they'll be back without problems.
- thrownthatway 5mo ago
  > It can just mean that nobody though about flooded streets No one who works for them thought of flooded roads. That’s reassuring.
  - onlyrealcuzzo 5mo ago
    They were only in Arizona for a long time...
    - forgetfreeman 5mo ago
      Assuming the rest of the continent is like Arizon also seems comforting...
      - onlyrealcuzzo 4mo ago
        Well fortunately the rest of the planet is a lot more similar to Arizona than Venus or the moon of the bottom of the Ocean, and they're already doing quite well in like 25 other markets, so...
        forgetfreeman 4mo ago
        ~80% of the population of the US lives east of the Mississippi, where road flooding is a dirt common event. Waymo's been smart so far to cherry pick markets that cater to their vehicles obvious limitations. That doesn't exempt them from criticism for failing to account for routine conditions in new areas they've chosen to move into. Additionally "doing quite well" is incoherent given it's been 17 years and Waymo is still unprofitable.
EA-3167 5mo ago
It’s been clear for a while to anyone without money riding on this that the relatively “easy” part fooled a lot of people into assuming that the last push to full self driving wouldn’t be radically greater challenge.
deleted 5mo ago
[deleted]
rawgabbit 5mo ago
Can Waymo cars even sense or detect flooded roadways? That is when it sees images of water covering the road, is it smart enough to know the car might get pushed into the raging waters? This is one of the reasons why I switched to Apple Maps years ago. Google Maps kept giving directions to small backroads that I knew were prone to flooding. I noticed it when Google announced they were changing the algorithm to save people gas or something.
- jmalicki 4mo ago
  It has lidar and radar, not just vision.
gensym 5mo ago
Yeah, it makes me wonder about their planned rollout to more of Southern California, where flooded roads aren't uncommon, especially in some of the valleys.
pj_mukh 4mo ago
"Don't they have simulators to test every weird and unexpected road condition offline? " I remember when this was brought up in a Cruise (RIP) crash. The situation was that another human driver had hit and run a pedestrian who had been flung across the street and under a Cruise self-driving car. The cars were getting complaints for making too many emergency stops in the middle of the street, so it dutifully dragged the lady in the under-carriage a couple of more feet to get off to the side of the road. Suffice to say that that had not coming up in simulation. P.S: Lady survived but the Human hit and run driver is still at large. No one wrote about them or cared.
Ekaros 4mo ago
To me standing water sounds like obvious thing to include in testing. And maybe even design some reasonable technical solution like sensors near say wheels. Areas with water should not be that uncommon that vehicles would never accidentally enter them. So seems like pools of say 10cm deep water should be included in testing.
- jmalicki 4mo ago
  A merely wet road (1mm of water) and one with 10cm can be hard to distinguish. If you avoid the former, you can't operate in rain at all.
vrighter 4mo ago
testing cannot prove the absence of bugs. It can only prove that you didn't find any, which is a completely different thing
sumeno 4mo ago
Just because there are real world failures doesn't mean they didn't do simulations. It could just mean the simulation didn't account for something different in the real world. The website for software engineers is assuming that a production failure means nobody did any testing before prod...
- fauigerzigerk 4mo ago
  So what you're saying is that something far worse happened here. They did test for flooded streets but some slight difference caused the model to fail in real life. To be fair, there will always be something that fails. So the more important question is probably the frequency and severity of those failures.

by grumbel 5mo ago

outside2344 5mo ago

The fact that they aren't a usual event is probably exactly the challenge here.

antonymoose 5mo ago
It may not be usual in Atlanta itself, but living on the Southeastern coast within a mile or two of the water, for 30+ years, it’s a surprisingly common occurrence. I’ve got old photos around of kayaking through downtown Charleston during college, for instance, where the street flooding is not only usual but a many times per season occurrence. Lots of seaside areas have the same issue.
- throwaway2037 5mo ago
  > it’s a surprisingly common occurrence That is wild. What happens to all of the flooded property? Do they tear-down and rebuild everything after every major flood? Or massive rennovations? It cannot believe this is truly possible as flood insurance would become impossible expensive.
trollbridge 5mo ago
I’ve lived in a place where it flooded every year or two. It floods regularly where I live now too. Locals know which roads to avoid and not to drive into a flood.
thrownthatway 5mo ago
Floods aren’t a usual even. Have you ever even been outside?
ranger207 5mo ago
I just moved from an apartment right next to where this Waymo got stuck: https://old.reddit.com/r/Atlanta/comments/1tj00sl/flooding_in_midtown_ooof/ https://old.reddit.com/r/Atlanta/comments/1tj00sl/flooding_i... and I can say that that particular intersection floods about every time it rains hard. That being said, yesterday's rain was particularly heavy and I hadn't seen that intersection flood that bad since before Waymo started being rolled out here

krackers 5mo ago

They can simulate "driving out of a raging fire" but not a flooded street? This seems like an admission that the fancy "world model simulation" doesn't actually mean much https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-frontier-for-autonomous-driving-simulation/ https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-f...

brookst 5mo ago
IMO there is a lot of daylight between “is not perfectly capable of simulating all situations and always used perfectly to the full capabilities of the system” and “doesn’t mean much”.
riknos314 5mo ago
No simulation is perfect, so ideally you have a feedback look constantly looking at new real-world data as it comes in and finding where the simulation has errors, and updating the simulation to improve the correlation between the simulation and the real world over time. My guess is they did have flooded street sims but the correlation was much lower than expected, or the details of the situation being simulated (lighting, building locations, how dirty the water is, ...) were sufficiently different from the situation that was encountered that the sim based training didn't generalize to the new context.

burnte 5mo ago

In ATL this happens often enough that it's not a shock when it happens, we have lots of drainage problems here. I agree that I would have assumed Waymo had tested in events like this, but clearly not. So what I can say is running in ATL is a great test case for these events, and also the people who live here don't do a better job than Waymo did. There were dozens of people who ruined their cars yesterday trying to drive through deep water.

QuercusMax 5mo ago
We had a story in the news this week about a Cybertruck driver who thought his Elonmobile was a boat because it has "wade mode" and deliberately drove into a lake! Humans are very stupid when it comes to driving through standing water!
- burnte 5mo ago
  I saw that just a day or two before wednesday! Hilarious timing.
- SR2Z 4mo ago
  To be fair if you take Elon Musk at his word the Cybertruck is supposed to have hermetically sealed powertrain components and be capable of exactly this.
  - mschuster91 4mo ago
    The powertrain is one thing, the more critical issue is the car's structure, including the ventilation system, all sorts of gaps - and also, all hollow spaces, in which you need to balance weep holes (to prevent water condensation and subsequent rusting or weird issues regarding temperature changes) against the ability for external water to end up there at all. Getting that right is a very expensive job and that's why you usually only see true (i.e. no visit to a shop needed afterwards) wade ability on large military vehicles and custom RV builds.
Muromec 5mo ago
As much as one could expect waymo to train on it, one could also expect a functioning city to not have flooded streets

marcosdumay 5mo ago

It can just mean that nobody though about flooded streets, what's way more reasonable than it seems because of the birthday paradox. But that also means they need a long time to adapt to a new situation. That may be very bad depending on how fine grained a situation is defined, or it may mean nothing and in a few months they'll be back without problems.

thrownthatway 5mo ago
> It can just mean that nobody though about flooded streets No one who works for them thought of flooded roads. That’s reassuring.
- onlyrealcuzzo 5mo ago
  They were only in Arizona for a long time...
  - forgetfreeman 5mo ago
    Assuming the rest of the continent is like Arizon also seems comforting...
    - onlyrealcuzzo 4mo ago
      Well fortunately the rest of the planet is a lot more similar to Arizona than Venus or the moon of the bottom of the Ocean, and they're already doing quite well in like 25 other markets, so...
      - forgetfreeman 4mo ago
        ~80% of the population of the US lives east of the Mississippi, where road flooding is a dirt common event. Waymo's been smart so far to cherry pick markets that cater to their vehicles obvious limitations. That doesn't exempt them from criticism for failing to account for routine conditions in new areas they've chosen to move into. Additionally "doing quite well" is incoherent given it's been 17 years and Waymo is still unprofitable.

EA-3167 5mo ago

It’s been clear for a while to anyone without money riding on this that the relatively “easy” part fooled a lot of people into assuming that the last push to full self driving wouldn’t be radically greater challenge.

deleted 5mo ago

[deleted]

rawgabbit 5mo ago

Can Waymo cars even sense or detect flooded roadways? That is when it sees images of water covering the road, is it smart enough to know the car might get pushed into the raging waters? This is one of the reasons why I switched to Apple Maps years ago. Google Maps kept giving directions to small backroads that I knew were prone to flooding. I noticed it when Google announced they were changing the algorithm to save people gas or something.

jmalicki 4mo ago
It has lidar and radar, not just vision.

gensym 5mo ago

Yeah, it makes me wonder about their planned rollout to more of Southern California, where flooded roads aren't uncommon, especially in some of the valleys.

pj_mukh 4mo ago

"Don't they have simulators to test every weird and unexpected road condition offline? " I remember when this was brought up in a Cruise (RIP) crash. The situation was that another human driver had hit and run a pedestrian who had been flung across the street and under a Cruise self-driving car. The cars were getting complaints for making too many emergency stops in the middle of the street, so it dutifully dragged the lady in the under-carriage a couple of more feet to get off to the side of the road. Suffice to say that that had not coming up in simulation. P.S: Lady survived but the Human hit and run driver is still at large. No one wrote about them or cared.

Ekaros 4mo ago

To me standing water sounds like obvious thing to include in testing. And maybe even design some reasonable technical solution like sensors near say wheels. Areas with water should not be that uncommon that vehicles would never accidentally enter them. So seems like pools of say 10cm deep water should be included in testing.

jmalicki 4mo ago
A merely wet road (1mm of water) and one with 10cm can be hard to distinguish. If you avoid the former, you can't operate in rain at all.

vrighter 4mo ago

testing cannot prove the absence of bugs. It can only prove that you didn't find any, which is a completely different thing

sumeno 4mo ago

Just because there are real world failures doesn't mean they didn't do simulations. It could just mean the simulation didn't account for something different in the real world. The website for software engineers is assuming that a production failure means nobody did any testing before prod...

fauigerzigerk 4mo ago
So what you're saying is that something far worse happened here. They did test for flooded streets but some slight difference caused the model to fail in real life. To be fair, there will always be something that fails. So the more important question is probably the frequency and severity of those failures.