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


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

Not sure about everywhere in the world.. in the UK majority of emergency signs on motorways were controlled by people. As smart motorways are being introduced now, I think computers take over a lot of the jobs previously held by people. I would imagine they’d still need some people incase anything went wrong or crashed though.

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


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.

Some of the roadside ones just have SD cards in them with whatever message they’re supposed to display.

The standalone ones for long-term road construction are typically just that – stand-alone, programmed to display the same info repeatedly for the X months of construction. Sometimes during a project they’ll move them and make them say a different thing.

The larger displays over the highway that display estimated drive times, amber alerts, accidents, etc are networked, typically controlled by the state department of transportation or other similar authority.