NCDOT classifies signs by type based on the size, fabrication method, support type and purpose. The parameters of the different NCDOT sign types are described in Table 901-1 of the NCDOT Standard Specifications. The following further clarifies sign types:
Type A: The purpose of Type A signs may be guidance, regulatory, or warning. They are large signs fabricated from multiple sheets of aluminum with attached “Z"-bars on the reverse. They may be erected on overhead sign structures, structural steel or wood posts.
Type B: The purpose of Type B signs may be guidance, regulatory, or warning. They are fabricated from one sheet of aluminum with attached “Z"-bars on the reverse. They may be erected on overhead sign structures, structural steel or wood posts.
Type D: The purpose of Type D signs is primarily guidance. They are fabricated from one sheet of aluminum with holes for bolting to supports on the reverse. They are erected on steel U-channel posts, square tube posts (manufacturer spec) or wood posts. The recommended maximum square footage (u-channel) is 24 sf. Three u-channel post installation should be outside of clear recovery area or behind guardrail.
Type E: The purpose of Type E signs may be regulatory or warning. They are fabricated from one sheet of aluminum. Legends and borders are silk-screened or reverse silk-screened. They are erected on steel u-channel posts, square tube posts or wood posts.
Type F (Route Marker Assemblies): The purpose of Type F signs is guidance. They may be an assembly of individual panels. Each panel requires only one sheet of aluminum to be fabricated. Legends and borders are silk-screened or reverse silk-screened. They are erected on steel u-channel posts, square tube posts, steel beams or wood posts. The recommended maximum square footage (u-channel) is 24 sf (elaborate or confirm).
Milemarkers (Reference Location Signs): The purpose of Milemarkers is guidance. They are fabricated from one sheet of aluminum. They are erected on steel (2lb) u-channel posts, square tube posts or wood posts.
Overlays: The purpose of Overlays is to amend an existing sign message. They may be installed on existing overhead or ground mounted signs and may require more than one sheet of aluminum. They are attached to an existing sign with rivets. (Include limits/ criteria of overlays)
Sign Numbers:
- 1-99: Type A or B signs erected on overhead sign structures
- 100-199: Type A or B ground mounted signs
- 200-299: Type A or B signs exit gore signs
- 300-399: Type D Signs
- 400-499: Type E Signs
- 500-599: Type F Sign Assemblies
- 600-699: Overlays
- 700-799: Proposed Type A or B signs on existing supports
- 900-999: Existing Type A or B signs erected on proposed supports
Milemarkers are not assigned numbers.
Consistent numbering helps in the fabrication and review of signs.
Each Type A and B sign is assigned a unique number (1, 100, 200, 700, 900) as the sign number also identifies a location. If a Type A or B primary sign has additional secondary or supplemental panels attached or mounted to it, all panels are assigned the same base number and a unique letter, starting with “A" for the top panel.
Example: a primary guide sign has a secondary exit number panel and a supplemental LODGING panel. The Exit number panel is sign number 101A, the primary sign is 101B and the supplemental LODGING is 101C.
Every instance of a particular Type E Sign (stop sign, yield sign, etc.) of the same design and size shall be assigned the same number. If a type E sign is of the same design as another but of a different size, it shall be assigned a different number. If mounted on the same support, all unique Type E signs shall be assigned a different number.
Examples:
A Wrong Way and a Signal ahead sign are mounted back to back on a steel u-channel post. The Wrong Way sign is 401 and the Signal Ahead sign is 402.
For Type F Signs, number 501 is assigned to an entire assembly of route markers panels and auxiliary panels. Each Type F location is assigned a unique number.
Relocated Type D, E and F signs are not assigned numbers.
If more than 100 numbers are needed for a particular range of numbers, a four-digit number shall be used for the whole range. Example: 1000-1999 for overhead signs.
Sign Number Assignment Order
To assign sign numbers, on each individual Signing Plan Sheet (or can number from left to right on strip map), number from left to right in one direction of travel of the - L- line. At the end of the plan sheet, number from right to left for opposite direction of the - L- line. For the - Y- Lines, start with the lowest numbered - Y- Line and number from bottom of plan sheet to top (one direction only) and from top to bottom of sheet.
