The events leading to their installation never happened, so I'd assume nowhere.

I remember seeing FALLOUT SHELTER signs around as a kid.

I still see them on some old buildings with thick stone or brick exteriors like town halls and post offices.

Similar signs were installed near highly contaminated parts of Russia, specifically Chelyabinsk near lake Karachay, one of the most contaminated places on earth.

https://www.damninteresting.com/in-soviet-russia-lake-contam...

The "evacuation route" and crossbars guiding you through can be seen (at least last time I looked) in Umatilla, OR.

US Army chemical weapons depot...they are disposing of some nasty stuff there. If there is a leak they shut down certain roads apparently.