This sounds very similar to the people who drove into lakes because the GPS told them too.

Looking on Google its very clear that bridge hasn't been used in a while, but of course you wouldn't have had a reason to inspect every mile of the course it plotted. Its all grass and dirt in front of it and the pavement of Kings Road just ends. I'm guessing the person who owns the farm at the bridge is a cousin (isn't everyone a cousin in GA) with the sheriff or highway department, and arranged to not have that bridge repaired to make a private dead end.

However its surprising that there is no sign at the beginning of the road. Oh right, rural Georgia.