Such detailed database of fine grained road geometry gets stale very quickly, due to road maintenance and road construction. In US highway lanes are shifted sideways frequently.

But are they not continuously updating the road database with their fleet?

For common routes, yes. For getting to John's house, where the path there sometimes floods, no.

So the first waymo to get to this less used road to john’s will not have the data rather than every waymo that travels down a new highway, that then becomes a problem if it rains.

One car with an issue of first coincides with rain on a less used road?

Well, it's closer to: any car with stale data and sufficient water depth is a financial and PR disaster. These cars are not cheap, and a tiktok of someone being driven into the water is even more expensive!

As soon as the car descends below what was mapped it should be able to know there is a discrepency.

Satellite monitoring is also available for detecting extensive road work which they could use to invalidate and send out something to remap.

Sure, if you drive around slow enough so you can stop in time. Lets say coefficient of friction is around 0.5. That means you can drive around town at a brisk 12mph, if you need to stop within 10 feet (with 0ms reaction time).

Earthquake or sinkhole?

I traveled to Austin 3 weeks ago and there were entire highways not on Google Maps.

Apparently they were built in just a few months.

There's some places where Apple still thinks I'm driving through a cornfield even though the development is a few years old, now.

I suppose I could inform them somehow, but it's not worth the bother.

I’m still amazed at the people who claim that Apple Maps is as good as Google Maps nowadays. If you live anywhere where there’s lots of development, it’s definitely not. It’s also terrible when businesses or places of interest move. My wife’s business moved a half mile down the road and a single message to google maps got it moved in a couple days. Apple Maps took about a year with multiple requests and even multiple messages to their special “escalation” email address.

I don't know how they don't notice thousands of users driving through these "cornfields" at 60mph every day, though. You'd have thought that'd raise some alert?

I’ve literally watched my car (only car around) trigger the yellow heavy traffic warning (because I was driving slow to look for something).

Yet thousands of cars doing 60 mph through a cornfield and over a river doesn’t trigger a “maybe a freeway was built here?”

Pretty sure they already rely on such a database for positioning, so they already have that problem.

But yes, this wouldn't work for other self-driving systems that don't rely on HD maps.