eli5, Who controls emergency signs on highways? Are they connected to the internet?

Question

I’ve seen this signage before, but I’ve never thought about how these signs get updated throughout the whole state instantly. TIA!

In: 2

Answer 1

In the US the standards are all grouped under NTCIP. Other countries use different standards.

https://en.m.wikipedia.org/wiki/National_Transportation_Communications_for_Intelligent_Transportation_System_Protocol

It covers lots of types of communication. Signs are one, but also stuff like traffic lights, and toll booths. This is all managed from centralized traffic control centers.

Actual communication can be done over any number of different physical means. Phone lines and serial lines used to be pretty common. Modern systems will go over the internet, with wired or mobile modems.