Here is an example of a single-line map of a course. It appeared in Measurement News #18, August 1986 as an example of an alternate style map. A supplemental course description removes any ambiguity about the path used on the roads.
I've certified many courses with maps of this type. A single-line map can be a lot clearer than the line-in-the-middle-of-the-road map, especially when the measurer does not take care to make the measured line take the proper tangents.