I never see any Flyover BeamNG.Drive only around the world. I ever Imagined who will be the first the to Build and Modelling the Road/Harbour Link/Girder Bridge into a Flyover Like Metro Manila Skyway that was 37 km Is it possibe???
Building and modeling large bridges and highway systems is certainly possible (I think one of the devs even went so far as to make a tutorial on modeling bridge guardrails), but not yet common in BeamNG.drive. The main reason for this is that the city environments in which they are most likely to be found have only become possibly fairly recently in the game's development. West Coast USA has some very nice flyover bridges and on-ramps, but nothing quite as long as those found in most major metropolitan areas (with the maximum size for a heavily detailed map being 4km x 4km, a 37km bridge is something of a challenge to replicate). With that said though, I do believe there are a few maps in the mod repository that contain long bridges.