We have several railroad bridges near Grayson used as highway bridges. Add a concrete deck, some guardrails, and you have a one-lane highway bridge. The two best known ones are ex-Eastern Kentucky Railway bridges, from a line abandoned in the 1930s(?).
There are also three ex-C&O bridges, but they were never formally adopted as highway bridges. People started using the abandoned line as a shortcut between two main roads, and drove on the ties. The state has barricaded them on the grounds that the decks (ties) are "structurally unsound", but it seems that that wouldn't be hard to fix.
No, they're not a two-lane bridge on a major road, but for a secondary highway it might be interesting to model one, with the associated signs and, possibly, two cars facing off in the middle, where neither driver would yield, so neither can go.
