Hi, the page you’re citing is outdated and historical, as seen at the top of the page. See https://wiki.openstreetmap.org/wiki/United_States_roads_tagging/Routes#California for current tagging guidelines applicable to California. If you think we should adopt the “CR” prefix, there should be some discussion in either https://community.openstreetmap.org/c/communities/us/78 or https://slack.openstreetmap.us/ .

Also, the format of ref=* on a route relation such as https://www.openstreetmap.org/relation/74885 should never include the alphabetic prefix, unless that prefix is presented as an integral part of the route number on signage. I undid this part of the changeset in https://www.openstreetmap.org/changeset/175010519 .