South Carolina/Major roads/Main
South Carolina follows the national guidelines for road types.
State secondary routes (those numbered S-##-###) are not considered County Routes for the purposes of road typing.
Unpaved roads (dirt, gravel, etc.), if unclassified or classified as Collector on Functional Classification maps, should always be set to the "Dirt road / 4x4 trail" type. If there is an unpaved road classed as an Arterial, it should be mapped according to Functional Classification.
In South Carolina we have a set minimum standard for locking roads based on segment type. Any road of a certain segment type must be locked at least to the rank (level) in the chart below. Roads may be locked higher for protection and special situations (areas with construction, tricky design, frequent mistakes, imaging inaccuracies, and the like), but should not be locked lower.
A great time to implement these locks is while bringing the road types of an area into compliance with the current US road type standards (FC and highway systems). Lock the roads based on type after they've been set to current US road type standards.
|Highest rank of connected segment|
Note: Certain areas may be locked higher than the above minimums. Please do not lower locks unless approved by the RC or a South Carolina SM.
State Highways should be named to match local signage and/or county GIS with the state highway name of SC-### listed as an alternate name. If there is no local name of a state highway then it should be named SC-###. The same rules apply to US Highways as well.
State Secondary Routes are state-maintained roadways that are not part of the state highway system. This number is typically signed with a small black sign at any such roadway. These 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 only be set as an alternate road name. In rare cases, a road will have this number and no name; in this case, it should be named "Rd XXX", with the full number as an alternate. For example, S-3-497 in Ulmer is named "Rd 497" with the alt name "S-3-497". Consult with the State Manager before changing a name to the "Rd XXX" system.
Both state highway numbers and state secondary route numbers can be easily accessed online with SC Street finder.
County Road numbers in South Carolina are usually not easily available and never signed; however, in places where they can be found more easily we use CR-XXX to mark them. Note some interstate exits will label a road as being "County Rd XXX". This does NOT mean that this is a county route; usually, they are state secondary routes.