Thanks for the useful input on these issues. I'm a long-time map editor on other platforms, but these issues are not readily apparent. On Open Street Map I usually just deal with roads and already-existing features.

6 MPH is really posted here. I drove it last week. See the photos of their map posted at the registration building: https://photos.app.goo.gl/PzgsTgT7BqJxNrNr5

I corrected it. Thanks for catching it.