This weekend I realized for the first time in my life that saying "highway 24" in south eastern Michigan could refer to two completely different streets that are within a few miles of each other... that go in similar directions...
We have this monstrosity near me. Highway N is north-south. Highway B is east-west but uses Highway N for about a mile, so for that stretch the highway is both B and N. Highway BN intersects with Highway B about a mile from Highway N and then parallels Highway N. I never realized how dumb it was until someone asked me for directions. They were so lost. I think they were on Highway B, and their printed directions said to turn on Highway B/Highway N. So they turned on Highway BN. It makes sense but was totally wrong. I hope I got them back on course.