Who is the signing authority? China? The United States? Russia?

Probably whatever authority is responsible for the sign installation/road maintenance.

Makes sense assuming that authority doesn't leak their private keys like a sieve.

Provided they have a way to easily rotate keys via access to the physical hardware it's probably fine. If a local government loses a signing key they would have to register a new one and send a work crew to swap a micro SD card in every traffic light or whatever, but at least that's all they would have to do. In the meantime all an adversary can do with their signing key is install fake beacons, but that requires actually fabricating beacons, and putting themselves at risk by physically installing them in a place they will quickly be noticed, so the potential for damage is pretty limited. Much like how people can already steal stop signs or put up their own speed limit signs, in practice I don't think this will be more than a nuisance.

> If a local government loses a signing key they would have to...

They'd have to know they were compromised first. I think that is a big 'if', and creation of a centralized repository of backdoor keys makes for tempting targets.

Also, a stake in the ground on the edge of the road that says, I'm 15 feet to the right of the center lane will probably pay for itself in a couple years of stripping. You put two in the ground that say, I'm 15 feet to the right of the centerline and 35 feet from the next beacon and you never have to paint a centerline there again.

But all you've done is swapped one thing that will be poorly maintained for one thing that's already poorly maintained.

*with a much longer life. Stripping needs to be done every year to stay fresh. You can put a beacon in the ground and I should be able to be there and working 10 years later.

Those beacons can be DoSed. Consider how Hong Kong protestors avoid the face recognition with laser pens.

Yeah, but couldn't you also simply disconnect the beacons with a wirecutter?

I mean, every technical system can be shutdown and will shutdown sometimes, isn't that a inherent weakness of such a system?

if that beacon does not respond disable automation for that part?

Sure, but I was thinking about temporary disabling (like a temporary, reversible DoS). If you can temporarily disable something, it is more difficult to find the culprit, and the impact is higher because of the surprise element. If something is permanently disabled, you fix it right away.

Just like bullying: bullying itself is annoying, but what I found annoying is the inconsistency of it. At some point, my bullies were friendly, at another point once more bullying. If it were permanently on-going and not sneaky, they'd be found out by e.g. teachers long ago already.

Ahh, yes that would be a problem.

On the other hand, wouldn't a ddos be visible in the logs?

Logs should be checked centrally anyway, so a 30 second flood of messages should be visible.

But in the end, you are right that it will be hard to do this the right way.