It’s a good idea to keep a map or road atlas for your state (and surrounding states where you may travel) in your vehicle as a backup to your GPS navigation system. From a preparedness point of view, a hard copy map or road atlas can’t be beat…
A GPS navigation system requires power, operational satellites, and good weather conditions. Under normal circumstances this is not a problem; but there are circumstances in which your GPS may not function. It is good preparedness to have (road and/or topographical) maps with local, state, and national coverage – any of which could assist you during ordinary travel, evacuation, or ‘bug-out’.
While I enjoy using and appreciate my own vehicle’s built-in GPS navigation unit, I have a personal preference for reading quality maps while getting a feel for the terrain or region and its roads. I find that a GPS unit and its relatively small screen size (compared to a road atlas) does not provide a large enough perspective. There’s nothing like opening a road atlas or topo map and viewing the lay of the land.
I keep several quality road atlas’ in my truck which cover not only my own state, but the various states around me (and a national road atlas). Theoretically I could travel anywhere in the U.S. without a GPS, without issue.