I do not recall any highway signs telling you to tune to a frequency modulated station for updates into certain parts of an area.
The signs do direct you to tune to amplitude modulated frequencies all over the country.
I would say the newbies didn’t see that liability coming.
AM has much better range plus it can “skip” which can send the signals hundreds of miles. I can recall when the clear channels would have people call from where in the country they were. Clear channels have just 3 call letters and share broadcast frequency with no other station.