I would only say "the" when I use the name of the bridge."a" or "the" before "bridge" - when I say "In the city, there is ? bridge", this bridge the only one in my city?
"Once you get to Bowie, you will see a bridge. Cross over it and make a right."
"Once you get to Bowie, you will see the Fox Hill Lake Bridge. Cross over it and make a right."