Note: There is an issue with basemap roads without a city and name being listed as in another state (most commonly Georgia or North Carolina). Double-check the state attribute of each road you edit! You can also use the Validator script to highlight roads with a state other than SC (custom check; template: ${state}, regex: !/^South Carolina$/).
Naming
State Highways should be named as SC-XXX. This includes both primary and alternate names for a road.
Secondary Routes should be named as S-##-XXX, where ## is the number of the county (alphabetical order, see chart above; Abbeville is 1, York is 46) and XXX is the route number (e.g. 18); the full name for route 18 in York county would therefore be S-46-18. This name should be set as the alternate road name(s), where appropriate, and only as the primary road name in rare circumstances. Consult with the State Manager before doing this.