NCDOT Roadway Design Unit: Glossary

ABBREVIATION AND ACRONYM

NOMENCLATURE		CIRCLE of RELATIVITY

S	South or Southern or Southing \| Scenic Beautification Projects (S-1234)	Roadway Plans
SABC	Sand Asphalt Base Course	Pavement Schedule
SASC	Sand Asphalt Surface Course	Pavement Schedule
SAU	Structure Anchor Unit	Roadway Plans
SBG	Shoulder Berm Gutter	Roadway Plans
SB (L)	South Bound (Lane)	Roadway Plans
SCS	Spiral Curve Spiral	COGO
SE	Super Elevation (Rate)	Roadway Plans
SEPA	State Environmental Policy Act	Project Permits
SI	Systeme International (French) \| Hazard Elimination Projects (SI-1234)	Pavement Schedule
SP	Shear Point or Super Pave	Pavement Schedule
SPD	Shear Point Diagram	Roadway Plans
SPDI	Single Point Diamond Interchange	Interchange Design
SPI	Spiral	Roadway Plans
SPUI	Single Point Urban Interchange	Interchange Design
SR	Service Road or Secondary Road	Roadway Plans
SS	Slope Stakes	Roadway Plans
ST	Spiral to Tangent (Point)	Roadway Plans
STA	Station	Roadway Plans
STBC	Soil Type Base Course	Pavement Schedule
STD	Standard	Drawing Standards
STIP	Statewide Transportation Improvement Program	Board Approval Process
STR	Structure	Roadway Plans
SREC	Struture Recomendations	Struture Recomendations
SUE	Subsurface Utility Engineering	Symbology Sheet
SUT	Single Unit Truck	Capacity Analysis
SYB	Symbol	Symbology Sheet

DEFINITION

spiral curve ƒ⁹ A transition curve of constantly changing radius placed between a high-speed tangent and a central curve; it permits a gradual speed adjustments.ƒ⁸ Typically, a minimum of 200' of spiral is required on interstate design. Also see CS, run off, run out, SC, and superelevation.

subgrade excavation - ƒ¹⁰ Excavation volumes that are backfilled with an earthwork material.

subsoil excavation - ƒ¹⁰ Excavation required to remove unsuitable material either 1) down to the bottom of the proposed template or 2) down to the bottom of the unsuitable material layer in cases where excavation limits are defined.

"suicide" lane ƒ¹ DOT jargon Term refering a five (5) lane undivided stretch of roadway with the middle 14' to 16' wide turning lane. There is no insinuation of negativity on the term "suicide". This terminology is not officially used in any standard NCDOT Roadway plans.