Just a couple of tidbits about the topics...hopefully this will answer some questions...the brown signs were first introduced in France in the mid 70's. They were used to show tourist attractions. They were brown as to not confuse the driving public on actual driving instructions, exits, towns, etc. All of the interstate sign and symbols you see today were developed in Europe and adopted here in the US with standards regulated by the Nat'l. Highway Traffic Safety Admin. States, counties and cities used their policy. Since Disney controls and maintains all of their access roads, they began to use their own designs and color schemes. I actually LOVE the red and purple signs...the first REAL hint you're entering your happy place!
As far as the radio station goes, the FCC allows and licences LPAM (low power AM) transmitters to be used to give information on traffic conditions, points of interest, etc. The transmitters are usually under 50 watts and have a very small coverage area (usually under a radius of a few miles). Hope this clears some things up and answers some questions...