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Comment by drob518 | Hacker News Reader

It’s a particularly hard problem in Texas. We get torrential rains and the landscape is relatively flat. Couple that with shallow soil over lots of limestone and it means flooding is really common. We also have roads that have a “low water crossing,” where a road crosses a creekbed that is normally dry but which will flood. There are often water depth signs there (basically a vertical ruler with feet marks so you can see where the water is up to). We lose people to this scenario (driving into flood waters) every year. It’s particularly problematic when it’s dark and you miss a warning sign. Before you know it, you’re in deep water and the flow can sweep the whole car downstream until it gets pinned against a tree, possibly with water forcing its way into the car.

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Yeah, people are bad at guessing and the usual "Plan continuation bias" kicks in.

I was travelling in a group to eat lunch with friends once, after heavy rains. We reached a site where the road needs to fit under a bridge and is known to flood, there's standing water, and the driver figured it's probably not too high, he drives in and nope, water over the air intake, bye bye engine and we walked the rest of the way to lunch

I absolutely should have said "No, don't" but the plan says we have to drive under that bridge, there is no plan B. Of course plan A being "Wreck car" is a stupid plan, but the bias meant I didn't say "No" and I should have.

You wouldn't die there, just trash the car, the flooding is localised - but there are definitely other sites around here where in flood conditions you could die if you drove into water that's deeper than you realised.

Uncle Rodney has left the crankcase.

This hits as someone currently babysitting an ornery Uncle Rodney

I love the irony of how you wrote this comment. You say bye bye engine, and then the very next action is to walk to lunch. No mention of what happened to the car, or whether the driver had to stay and deal with it. Nope, the most significant effect on you was that you had to continue on without the car in the picture. Hunger is the real plan continuation bias.

"Hunger is the real plan continuation bias."

Oh man, that brings a memory of a old roadtrip. We were guests at a house of a old british lady in a olive farm in southern france - and dinner was ready.

It was also unusual cold, so the fire in the chimney was burning very hot. And apparently it was not build for that, as the isolation and already some wood outside the chimney on the roof was suddenly starting to slowly glow and burn. In other words, the roof was literally starting to be on fire. But they were already sitting at the table and seriously wanted to eat first and care about the problem that the house was burning later. Well and so they did. So we put out the fire and ate later.

We all took off our shoes and socks and waded to dry land, then walked to lunch, arriving late and damp. A specialist recovery company moved the dead car to a repair yard and later the mechanics replaced the engine I think?

The bias isn't really about hunger, humans just tend to stick to an existing plan even once available evidence suggests that plan can't work, that's why those "Low bridge, divert" signs are less effective than you'd expect, why Olivia Rodrigo's "Fuck it, it's fine" is so recognisable for relationships, and why pilots end up scud running in a little plane after setting off in marginal visual conditions.

yes... and why the focus of your plan was still lunch!

This case makes me think of my brother's place in rural Tennessee. To get to his house, you drive through a small creek, year round. For a hundred years in their community, they've managed without a bridge. I'm not sure driverless cars are ready for edge cases like this. Also, no one tell Enterprise I drove their rental through a creek.

Heck, that was the way I took into the city for work for a few years, shaved a good 30 mins off the commute.

You'd have to hold off for a few weeks every season change while the ice hardened up/melted or get stuck in it (thankfully I tended to get there after someone else found out).

There are many fords in the U.K., and one particularly notorious one, Rufford Ford, ate about one car a day until it shut a few years ago, and one or two people would need emergency services to rescue them every month.

Frankly, you never know when you’re going to have a bad day - I managed to inflict several thousand euro of repairs on my pickup a few months back driving through water that didn’t even come up to the axles - because unbeknownst to me some shithead mouse had chewed through the top of the fuel hose, and water got into the diesel.

So, I expect driverless cars to struggle just as much as humans do.

https://www.bbc.co.uk/news/uk-england-nottinghamshire-676414...

Texas has it easy.

I've seen several places in England (and at least one in the western United States) where they have fords.

For those not familiar, water runs over the road full-time, and people are expected to just drive through it like it's no big deal. Except for right after a storm, when it is a big deal. It's essentially the intersection of a road and a stream where a bridge should be, but nobody ever built one.

For example: https://maps.app.goo.gl/eqjHKqDxGxFNz47D7 complete with the google streetview car (presumably) driving through it

And a collection of videos https://www.youtube.com/@jawalton2001/videos - it goes without saying, these aren't major thoroughfares.

Ha, the stream is not that bad in 2021 when the Google car drove it in your link. But if you go forward two steps, the date changes to 2024, and if you pan back to the river there is a much stronger/higher flow. Maybe they drove through it in 2021 but said no in 2024.

Also, there's a quizzical cow up the road a bit and now I want to live in this place. Thanks.

My dad went through one of those in England where it was a bit deep. The car had to have a new engine.

Make a mental note of the level of the air intake for the engine in your car, if the water doesn't make it that high you should be fine as long as you don't get stuck (no, i don't where it is on my car).

The engine gets damaged when water gets into the piston chamber i think. Water compresses less than air so important things bend or crack if the engine is running too long with water in it.

I wonder how electric cars fare with deep water.

I wonder how electric cars fare with deep water.

The ground clearance for my EV is 7 inches. The manual specifies it can handle 18 inches of water.

I don't know if that's the point where water messes with the electronics, or a swift current would start to move it sideways.

> I don't know if that's the point where water messes with the electronics, or a swift current would start to move it sideways.

Flotation might also be a possibility?

Less of a possibility than in a similar combustion vehicle, though, since EVs tend to be heavier.

It’s probably all well and good until a vehicle gets old and gaskets no longer seal, immersion becomes more of quicker contributor to failure, electric or not. E.g. cracked boots on a ball joint or not so sealed wheel bearings.

Also why I don’t like pressure washing anything mechanical.

E.g. Drove through a heavy rain storm and my ecu decided one of my wheel speed sensors was faulty and suspended my abs and traction control. Even after drying it out on a nice day of driving, the error persisted but I was able to reset it with my vehicle specific obd reader and not an issue again. Ugh.

I fear that advice might make some people overconfident when the water isn't stationary. Flooding doesn't have to be that intake-high to sweep a car sideways off the road.

All liquids are incompressible- water doesn’t compress at all.

It seems to me you could do something interesting with floating warning devices that only appear when the water's too deep.

Sounds like overkill.

Stick in the ground will do it.

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...

As long as the ground doesn't dip halfway across...

You can see ripples in the waters surface when there’s a hole in the crossing.

At least when the average depth is shallow enough you’d want to cross in a normal vehicle.

If in doubt, walk it first. (Unless you’re in an area with crocodiles, of course.)

If you can’t walk the crossing, then under no circumstances should you drive it.

I've lived here over a decade. Lived through multiple floods. Never once have I driven into water without being unaware of it.

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