Earlier quoted context omitted.
I guess that depends on country. For example the UK has no public road (that I'm aware of) where a speed of higher than 70mph is allowed, so that would be an easy initial rule. Where there are dynamic speed limits in place, it would be plausible to report back possibles (car location and speed) which could then be checked against a central database which was more accurate. I'm not suggesting that such a system is a g…
In the US this sort of detection is privatized - by insurance companies lowering your rates if you run their app which beans your location, speed, and motion/fitness data to their servers. At least for Allstate you need 50 drives a month to qualify for the discount, and hard braking or speeds over 80 disqualify a drive from being counted for the discount.
The really stupid thing about this is that driving 80+ and the occasional hard braking is just normal traffic condition on some roads at some hours. Penalizing people for needing to use those roads at those times and acting like every other normal human around them when doing so defeats the point of insurance.