From reading the comments it looks like they are all over the place. I know of several all over Indiana, especially southern Indiana where I live now. There is actually a covered bridge festival every year in the area where there are dozens of covered bridges in a very small area, most of which are only one lane. There are also a lot of rural gravel roads that are only wide enough for one vehicle but are for traffic in both directions. when you come across someone coming from the opposite direction you just kind pull half way off the road and drive by each other. Most of the time there isn't much traffic anyway. Thanks for sharing