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.
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…
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.