Good example. Another common example is one-way streets. If you have several sections of a street with conflicting one-way markings like this: ----> . <

Good example. Another common example is one-way streets. If you have several sections of a street with conflicting one-way markings like this: ----> . <---- . ----> then the street becomes unroutable (assuming no intersections at the .s). I found this was a fairly common issue on the entry/exit flares at roundabouts.