I took a trip from central Maryland, to Wierton West Virginia, to Columbus Ohio than down to Tyler County West Virginia, than back to central Maryland.
I was using Tom Tom navigation on my Treo 650 cell phone. It was fine untill the return trip. My cell phones navigation locked up twice on the way home through the mountains. I just assumed either the phones RAM was full, or it was switching maps and locked up, or it lost satelight signal, but it seems this happens with long trips and GPS sometimes. I think it just lost signal and crashed personally, either that or the GOVT jammed it (for w/e reason) or it may have just been an electrical storm, or power lines, you never know. Just restart it and move on