We've only been in Bulgaria for a day and a half, but there are some things we've noticed already. One of the first things is that the roads are not in very good condition! We missed a pothole yesterday that would have done some serious damage. It was a crater! And this is on a major two lane road that is part of the vignette toll system with a lot of truck traffic.
Also, the roads we've been on so far have no shoulder. But there are pulloffs every few kilometers.