Lesson 1. Some bridges are not high enough to accommodate a large commercial vehicle. It may, at times, appear to be convenient to use your truck as a measuring tool but that can get very costly over time. See the following example:
Stuck Whiskey Truck Spills Load on Road | NBC Washington
Extra Credit: Treat all loads of booze as though they were your own. If you don't drink, treat them as though they were mine.
Lesson 2. Some bridges were not designed to accommodate the weight and girth of a large commercial vehicle. Come to think of it, I can't recall that I've ever seen a rustic old covered bridge that was intended to carry a modern big truck. Always consult with your insurance company to confirm your coverage before you cross rustic old covered bridges. See the following example:
Tractor trailer closes historic Lancaster covered bridge - Thursday, May. 27, 2010
Lesson 3. Some bridges have narrow entrances, are accessible only via sharp corners or both. Never use a bridges structural components to "shoe horn" your way onto them. Bridge and trailer repairs can be very expensive. Few municipalities have extra cash to make bridge repairs while they hunt you down and you may be forced to lower your expectations on the selling price of your trailer. See the following example:
Police seek driver of tractor-trailer that damaged Stark Street bridge | OregonLive.com
I hope you find this training helpful. I can think of at least three people who could have benefitted from it. Hopefully, you will, too. Your new or prospective employer thanks you.