This has been going on for many years now and is really nothing new besides increasing the network that these signs make up.
TACKAMARKS, known as TACMARS are part of a very elaborate directional code system that is meant to guide military in the event of a national crisis, or so they want us to believe. TACMARS can be found on the backs of road signs across our nation. They (our gov) wants us to believe that the highway systems were set up for economy and travel. Indeed they were but that's not the first reason they were created. They were put in place for troop movements. So why these mystical secret codes on the backs of signs - after all our troops can read a map and know the land and the language, right? TACMARS are put in place for foreign troops, or UN troops to be able to find their way to strategic locations (because they all may not be able to read and understand English), such as staging areas, helicopter landing sites, housing (or concentration camps), etc. Right now there are empty housing units in many strategic places across the country to house people that may need to be evacuated because of a biological attack for example. Sure, I suppose this could be true, but that's not why these places were built. The purpose of such housing is to have a place to put the "dissenters" like you, me, people that are on a list somewhere that know too much or will not surrender their weapons.
There's a ton of information that can be shared on this subject. Since I don't think anyone wants to read pages of my rantings about this, you can check this site out. It's a fairly decent attempt to bring out this information.
[link]http://www.tackamarks.freeservers.com/[/link]
If you do have time to make it to this site, you'll notice that MI comes up a lot. Michigan is a very strategic location for this eventual master plan because of its fresh water and access to anywhere in the world through the Great Lakes. TACMARS can be found everywhere in this state.
Take it for what it's worth - just more for you to think about.