You can't trust just the GPS. We use the new model Rand that has our height entered. It is not suppose to allow us to route anywhere there is a bridge 13'5" or less.
On one occasion this year, in the state of Washington, it allowed us on a route below our height restriction. It was a RR overpass in a city while routing us to a CG. It has warned us on many other routes because I have tested it when not pulling fiver.
This is why I always check for low clearance issues using my Truckers Atlas the night before heading out. I got lazy a couple of times and almost paid the price.
