I am surprised there are not laws to have cars alert you to the fact your speeding for the systems that can read speed limit signs in addition to have current maps.
Well, there are systems that do this. Many new cars have speed limit sign recognition built in and they will display the current limit on the dashboard(and sometimes show you an icon indicating that the vehicle thinks you are speeding).
The reason why this is not more aggressive is because it's only seemingly a simple problem - in reality it's far far from it. In my experience of driving around the EU - I had a Mercedes CLS(brand new 2019 model) with adaptive cruise control and speed limit signs recognition, and while amazing when it worked, it worked maybe 50% of the time. Issues I noticed:
1) it kept detecting speed limit signs on roads parallel to the one I was on [0]
2) it kept detecting speed limit signs on side roads - leading to actual dangerous situations, because I was on a 50mph road, going past a 20mph side street and the car would suddenly hit the brakes because it detected a 20mph speed limit. That's 10000% unnacceptable in a production vehicle. [1]
3) it kept reading speed limit signs on the slip roads leaving the motorway - so you're doing 70mph on the motorway, and it suddenly reads the 50mph speed limit that's for the motorway exit. Same problem as with point 2.
4) In situations where there are no speed limit signs, it would use the map data - and even though this was a brand new, March 2019 vehicle, it had no idea that a stretch of motorway next to my house is not limited to 50mph anymore, and hasn't been for the last 2 years.
In practice, I had to keep overriding the speed limit chosen by the car constantly, and after few days I switched it fully off as it led to me nearly shitting my pants as the car hit the brakes for seemingly no reason whatsoever few times.
And then I have concerns about countries where the speed limit is only valid to the nearest intersection - and the definition of an intersection varies. There are paved roads merging with the main road which are not intersections because the side road leads to private property, and then there are dirt tracks which are intersections because technically it's a public road open to motor traffic. There are no signs to indicate either - the driver is just "supposed to know". It's idiotic, I know. And in some countries(Poland) the speed limit can change as often as 4-5 times in a span of a single kilometre. What's even worse is that there are situations when the speed limit can actually increase(!!!!) the speed limit set in a certain zone(built-up zones have a 50km/h speed limit, but this can be increased by a regular speed limit sign - and then yes, it goes back down(!!!) to 50km/h after an intersection). All of this stuff would be incredibly hard to code into a system like this, and it's one of the reasons why I suspect the proposal made by EU to have automatic speed limiters built into cars will either fail, or people will just keep disabling it altogether, making the whole idea pointless.
[0] Here it would think the side road has a speed limit of 50mph, because it would read the wrong sign:
https://www.google.pl/maps/@54.9929676,-1.5788994,3a,75y,78....
[1] Here for example the 20mph sign is placed at an angle to the road, so the car would read it going past it - and set the adaptive cruise control to 20mph which is incorrect for this street:
https://www.google.pl/maps/@55.0074774,-1.615172,3a,41.3y,90...
Same here:
https://www.google.pl/maps/@55.0071611,-1.6214135,3a,75y,240...
My sister has an insurance policy with a tracker(because she's quite young and there was no other option for her) and one day we noticed that her insurance score has fallen down through the floor, hugely negative points for....speeding. Of course the website doesn't tell you where or when, just that you're being penalized for being naughty. Ok, so we call them up, and they say they will send us the exact coordinates where the "offence" happened. Ok, cool - and turns out that they thought she was driving 70mph on a road going next to the motorway - which had a 20mph speed limit. Which was literally physically impossible, as previous GPS points were showing her on the motorway and there was no direct exit to that smaller 20mph road. So the GPS was off by maybe 10-20 metres at most, but the insurance has automatically penalized her massively for speeding. What's stopping the same system from failing when used for automatic speed limit adjustment? Especially in some extremely dense cities where you literally have roads of varying speed limits overlapping each other.
The insurer did correct that score penalty manually after I complained. But it's still a joke that it could make that mistake in the first place, especially since they can literally cancel your insurance due to speeding.
Google maps was (dangerously in the winter) directing people to an old road, into mountains after a new one had been built. It took national news, and several months of attempts to get them to update it.
The just build a big very accurate database approach is the one I would absolutely guarantee will never work.
If there is something out of date, hit the report button and it's typically acknowledged immediately, confirmed in a few hours, and public within a few days.
Tesla Model 3 has this feature and, while autopilot is engaged, will decrease the speed of the car when the speed limit decreases.
If it's a proposal by the government, they could do better: they could mandate not only automatic speed limiters, but also something embedded in the roads like balises (https://en.wikipedia.org/wiki/Balise) to reliably indicate to the car the correct speed limit.
The core idea is to continue to grant enough agency to the operator that they are held responsible as long as the vehicle faithfully executed the intent.
The tongue and cheek bloodsport throttle in the real world would instead be a proactive user choice of how much human guidance and interaction is required (solving the handoff problem, for example, 1 minute automatic, 1 minute manual or an automatic system that you'll need to irritatingly press a button every few minutes to stay engaged).
If a user options for "zero engagement" (let's pretend they're drunk or just got out of surgery), then there has to be a visceral experience of the underlying risks; a constant beeping and flashing, some real sense of urgency and warning.
I know it's a luxury product but cars are machines of carnage where death is never more than a mistake and mere seconds away. That reality should supercede.
This may be eventually removed, but a system like this would honestly solve all the current issues
Just like trains! There is an alarm system just as you describe. After a certain amount of time, there are audio and visual warnings for the engineer. The engineer must engage the switch to "snooze" the alarm, and in the event that the engineer does not engage, the train automatically cuts power to throttle to brake.
I'm not sure flashing lights and a klaxon are what we would want in a car, but maybe beeping akin to lane assist that quickly increases in volume + a light on the dash would be a good start.
Europe is mandating this (combined with limiting) for new cars soon. It will be possible to override 'temporarily'.
1) I don't believe we'll go "autonomous cars only" for predictable future. I can see that happening on limited set of streets(say, strict city centres), but not overall. Mostly because I think requiring everyone to buy an autonomous car is ridiculous, and then there are cars made even right now that I can totally see people driving in 20/30/50 years from now. We'll always allow manual cars on the road, just like we still allow horses - it just became so rare that in practice it's not an issue to have an animal with no safety features on the road next to modern motor vehicles.
2) there will always be users of the road that cannot be made automous - motorcycles. Unless you believe that motorcycles will be banned, but I don't think that will happen.
So yes, I think any speed limits of the future will be set for humans first and foremost. I do look forward to those speed limits to be revised up though - cars are far safer and more efficient at higher speeds than they were few decades ago, and yet speed limits have never been revised to reflect that. US is particularly bad at this, with empty stretches of straight road having a speed limit of 50mph for instance. That should have been fixed years ago.