171–180 of 223 posts
That's a tough problem - distinguishing wet pavement from deep water. Humans make that mistake frequently. Autonomous vehicles should probably be equipped with a water sensor. (We did that in our DARPA Grand Challenge vehicle back in 2005). Then they can enter water very cautiously and see if it's too deep. This may make them too cautious about shallow puddles on roads, though.
That's a tough problem - distinguishing wet pavement from deep water. Humans make that mistake frequently. Autonomous vehicles should probably be equipped with a water sensor. (We did that in our DARPA Grand Challenge vehicle back in 2005). Then they can enter water very cautiously and see if it's too deep. This may make them too cautious about shallow puddles on roads, though.
I thought the same thing. A very small float switch would work here. Somewhere between the radiator and the bumper. Fording depth is different for every vehicle.
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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…
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 t…
That's the promise of self-driving cars. Every time an issue is found, no matter how minor, it's fixed and updated everywhere. From now on, every car of that model (and future models, and related models) will no longer have that problem. Several passes of that improvement cycle, and self-driving cars become safer (and more efficient/comfortable/etc) than human drivers. At least, that's how it's supposed to work.
It's likely they patch this and cause 2 other bugs in the process.
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LIDAR isn't helpful for water. Standing water behaves like a mirror on LIDAR.
Could you use a different spectrum of EM radiation to detect water? There are parts of the microwave band that attenuate the signal by absorption and I wonder if you could use that. The only clue a human driver has in that situation is in the visible spectrum. The lines of the road disappear from view, which can be challenging to see at night.
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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…
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.
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...
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Reminds me of all the Waymo vehicles stalled during that San Francisco blackout a while ago. I have always believed that when people cite statistics on Waymos beating human drivers on safety statistics, that is only in the case of the happy path, or "happy road". The safety statistics could plummet in specific scenarios that lack training data or forethought, and they could crop up at any time.
Right, but humans are terrible at the happy path. I’d take 20% safer on the happy path over 40% less safe in unforeseen circumstances. The failure mode being “stopped car” is also not that bad.
Also I suspect many “unforeseen” circumstances happen regularly. The unforeseen part is “what” and “when.”
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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…
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.
Flotation might also be a possibility?
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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 t…
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.
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.
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I thought the same thing. A very small float switch would work here. Somewhere between the radiator and the bumper. Fording depth is different for every vehicle.
Going to move up and down with every bump and pothole
Since the densities differ, water will cause the rod to rotate. But since the masses are the same, bumps will create no net torque around the pivot point and thus no rotation.
ASCII art diagram:
F------(x)------C
(x): pivot point
F: float
C: counterbalance
I'm sure there are other ways like sensing the electrical resistance of the water.
Or just let the float sensor bounce. It's underwater when it stops bouncing and is continuously in the up position.