This is a great use of this technology. In aggregate, these hard braking events _do_ tell us about road design issues. They also tell us about problematic drivers, in aggregate.
I'll never use one of these dongles, though, because I don't want my every move second-guessed. There's nothing _inherently_ dangerous about isolated hard braking or cornering or acceleration events. It all depends on context. Am I braking hard to avoid an obstacle or mistake by another driver? Is there someone behind me that's likely to rear-end me, or am I in the middle of a highway in the desert? Did I just replace my brake pads and I'm bedding in the new pads?
I don't want to have to worry about whether I've used up my invisible quota before the algorithm decides I should be moved into a more expensive insurance bracket.
> There's nothing _inherently_ dangerous about isolated hard braking or cornering or acceleration events.
I have to hope that the actuaries at the insurance company are well aware of that. Tuned correctly, the algorithm should not unfairly penalize you.
I am reminded of my mother-in-law. She has very few at fault accidents in her decades of driving. And yet she has been involved in a statistically unlikely number of major wrecks. She would say that she is a safe driver, because she is not found at fault. I think it more likely that she is an unsafe driver who creates situations where accidents are more likely to occur but in a way that will not peg her as the underlying cause. Her rates should go up. As should yours, if you are experiencing a very abnormal number of hard-braking events even though you can ascribe every one of them to something outside of your control. Because the implication is that something about your driving habit is increased risk.