Vertical Alignment
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Child Classes
Property Sets
- Alignment General
- Vertical Alignment Reference
- Vertical Alignment Offsets
- Sight Distance
- Vertical Alignment Grades
- Vertical Curve Type
- Vertical Curve Lengths
- Vertical Alignment Key Stations and Elevations
Applicability
This specification applies to all Vertical Alignments. It also addresses the child class Vertical Alignment Curve. It also addresses the child class Vertical Alignment Tangent.
Child Classes
Vertical Alignment Curve
This child class inherits the requirements defined for the parent element.
Vertical Alignment Tangent
This child class inherits the requirements defined for the parent element.
Property Set: Alignment General
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
alignment-id |
Unique identification of the alignment for reference for vertical alignment, corridor elements, and other roadside components. | String | required | |
alignment-description |
Description of the alignment to further explain purpose and/or location. | String | required |
Requirements
- All Vertical Alignments must have the property Alignment ID in the set Alignment General.
- All Vertical Alignments must have the property Alignment Description in the set Alignment General.
Property Details
Alignment ID
Unique identification of the alignment for reference for vertical alignment, corridor elements, and other roadside components. Requirement: All Vertical Alignments must have the property Alignment ID in the set Alignment General.
Alignment Description
Description of the alignment to further explain purpose and/or location. Requirement: All Vertical Alignments must have the property Alignment Description in the set Alignment General.
Property Set: Vertical Alignment Reference
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
horizontal-alignment-id |
The horizontal alignment to which the vertical alignment is associated. | String | required |
Requirements
- All Vertical Alignments must have the property Horizontal Alignment ID in the set Vertical Alignment Reference.
Property Details
Horizontal Alignment ID
The horizontal alignment to which the vertical alignment is associated. Reference: TPF-5(480) SME Consensus Definition Requirement: All Vertical Alignments must have the property Horizontal Alignment ID in the set Vertical Alignment Reference.
Property Set: Vertical Alignment Offsets
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
offset-from-horizontal-alignment |
The distance measured from a primary alignment (centerline of the road) to another point of interest, such as a secondary road, lane, or feature like a shoulder or barrier. | Real | Feet | optional |
Requirements
- All Vertical Alignments may have the property Offset from Horizontal Alignment in the set Vertical Alignment Offsets.
Property Details
Offset from Horizontal Alignment
The distance measured from a primary alignment (centerline of the road) to another point of interest, such as a secondary road, lane, or feature like a shoulder or barrier. Requirement: All Vertical Alignments may have the property Offset from Horizontal Alignment in the set Vertical Alignment Offsets.
Property Set: Sight Distance
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
headlight-sight-distance |
Stopping sight distance for a sag vertical curve | Real | Feet | optional |
stopping-sight-distance |
Stopping sight distance is the distance necessary for a vehicle traveling at or near the design speed to stop before reaching a stationary object in its path. For vertical alignments, applies to crest vertical curve. | Real | Feet | optional |
passing-sight-distance |
On two-lane, two-way roadways, provision for a vehicle to pass a slower vehicle while occupying the lane regularly used by opposing traffic. | Real | Feet | optional |
k-value |
The horizontal distance needed to produce a 1% change in gradient. | Real | Feet | optional |
Requirements
- All Vertical Alignments may have the property Headlight sight distance in the set Sight Distance.
- All Vertical Alignments may have the property Stopping sight distance in the set Sight Distance.
- All Vertical Alignments may have the property Passing sight distance in the set Sight Distance.
- All Vertical Alignments may have the property K-Value in the set Sight Distance.
Property Details
Headlight sight distance
Stopping sight distance for a sag vertical curve Reference: New York State Department of Transportation Highway Design Manual Requirement: All Vertical Alignments may have the property Headlight sight distance in the set Sight Distance.
Stopping sight distance
Stopping sight distance is the distance necessary for a vehicle traveling at or near the design speed to stop before reaching a stationary object in its path. For vertical alignments, applies to crest vertical curve. Reference: New York State Department of Transportation Highway Design Manual Requirement: All Vertical Alignments may have the property Stopping sight distance in the set Sight Distance.
Passing sight distance
On two-lane, two-way roadways, provision for a vehicle to pass a slower vehicle while occupying the lane regularly used by opposing traffic. Notes: Could be determined in construction Reference: New York State Department of Transportation Highway Design Manual Requirement: All Vertical Alignments may have the property Passing sight distance in the set Sight Distance.
K-Value
The horizontal distance needed to produce a 1% change in gradient. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignments may have the property K-Value in the set Sight Distance.
Property Set: Vertical Alignment Grades
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
incoming-grade-g1 |
Slope of profile as it approaches a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance | Real | required | |
outgoing-grade-g2 |
Slope of profile as it departs a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance | Real | required | |
incoming-grade-g1-2 |
Slope of profile as it approaches a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance | Real | required | |
outgoing-grade-g2-3 |
Slope of profile as it departs a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance | Real | required |
Requirements
- All Vertical Alignment Curves must have the property Incoming Grade (G1) in the set Vertical Alignment Grades.
- All Vertical Alignment Curves must have the property Outgoing Grade (G2) in the set Vertical Alignment Grades.
- All Vertical Alignment Curves must have the property Incoming Grade (G1) in the set Vertical Alignment Grades.
- All Vertical Alignment Curves must have the property Outgoing Grade (G2) in the set Vertical Alignment Grades.
Property Details
Incoming Grade (G1)
Slope of profile as it approaches a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance Requirement: All Vertical Alignment Curves must have the property Incoming Grade (G1) in the set Vertical Alignment Grades.
Outgoing Grade (G2)
Slope of profile as it departs a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance Requirement: All Vertical Alignment Curves must have the property Outgoing Grade (G2) in the set Vertical Alignment Grades.
Incoming Grade (G1)
Slope of profile as it approaches a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance Requirement: All Vertical Alignment Curves must have the property Incoming Grade (G1) in the set Vertical Alignment Grades.
Outgoing Grade (G2)
Slope of profile as it departs a specific point. Typically expressed as a percentage, indicating the vertical rise or fall over a horizontal distance Requirement: All Vertical Alignment Curves must have the property Outgoing Grade (G2) in the set Vertical Alignment Grades.
Property Set: Vertical Curve Type
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
symmetrical-curve |
A vertical curve in which the Point of Vertical Intersection (PVI) is located at the midpoint between the Point of Vertical Curvature (PVC) and the Point of Vertical Tangency (PVT). This configuration results in equal curve lengths on both sides of the VPI, providing a balanced transition between grades. | Boolean | required | |
unsymmetrical-curve |
A vertical curve in which the Point of Vertical Intersection (PVI) is not located at the midpoint between the Point of Vertical Curvature (PVC) and the Point of Vertical Tangency (PVT). This results in unequal lengths of curve before and after the PVI, typically used when design constraints require different approach and departure grades or limited space. | Boolean | required |
Requirements
- All Vertical Alignment Curves must have the property Symmetrical Curve in the set Vertical Curve Type with a value being one of Yes, No.
- All Vertical Alignment Curves must have the property Unsymmetrical Curve in the set Vertical Curve Type with a value being one of Yes, No.
Property Details
Symmetrical Curve
A vertical curve in which the Point of Vertical Intersection (PVI) is located at the midpoint between the Point of Vertical Curvature (PVC) and the Point of Vertical Tangency (PVT). This configuration results in equal curve lengths on both sides of the VPI, providing a balanced transition between grades. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves must have the property Symmetrical Curve in the set Vertical Curve Type with a value being one of Yes, No.
Unsymmetrical Curve
A vertical curve in which the Point of Vertical Intersection (PVI) is not located at the midpoint between the Point of Vertical Curvature (PVC) and the Point of Vertical Tangency (PVT). This results in unequal lengths of curve before and after the PVI, typically used when design constraints require different approach and departure grades or limited space. Synonyms: Asymmetrical Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves must have the property Unsymmetrical Curve in the set Vertical Curve Type with a value being one of Yes, No.
Property Set: Vertical Curve Lengths
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
length-of-vertical-curve |
The horizontal distance in feet from the PVC to the PVT. | Real | Feet | required |
middle-ordinate-mo-vertical |
the maximum distance between the midpoint of the curve and the midpoint of the long chord. | Real | Feet | required |
Requirements
- All Vertical Alignment Curves must have the property Length of Vertical Curve in the set Vertical Curve Lengths.
- All Vertical Alignment Curves must have the property Middle Ordinate (MO) - Vertical in the set Vertical Curve Lengths.
Property Details
Length of Vertical Curve
The horizontal distance in feet from the PVC to the PVT. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves must have the property Length of Vertical Curve in the set Vertical Curve Lengths.
Middle Ordinate (MO) - Vertical
the maximum distance between the midpoint of the curve and the midpoint of the long chord. Requirement: All Vertical Alignment Curves must have the property Middle Ordinate (MO) - Vertical in the set Vertical Curve Lengths.
Property Set: Vertical Alignment Key Stations and Elevations
| ID | Description | Type | Units | Cardinality |
|---|---|---|---|---|
point-of-vertical-curvature-pvc-station |
The station of the point at which a tangent grade ends and the vertical curve begins. | Real | Stationing | optional |
point-of-vertical-curvature-pvc-elevation |
The elevation of the point at which a tangent grade ends and the vertical curve begins. | Real | Feet | optional |
point-of-vertical-intersection-pvi-station |
The station of the point where the extension of two tangent grades intersect. | Real | Stationing | optional |
point-of-vertical-intersection-pvi-elevation |
The elevation of the point where the extension of two tangent grades intersect. | Real | Feet | optional |
point-of-vertical-tangency-pvt-station |
The station of the point at which the vertical curve ends and the tangent grade begins. | Real | Stationing | optional |
point-of-vertical-tangency-pvt-elevation |
The elevation of the point at which the vertical curve ends and the tangent grade begins. | Real | Feet | optional |
high-point-station |
The station at the highest point on a curve where the gradient changes from positive to negative. | Real | Stationing | optional |
high-point-elevation |
The elevation at the highest point on a curve where the gradient changes from positive to negative. | Real | Feet | optional |
low-point-station |
The station at the lowest point on a curve where the gradient changes from negative to positive | Real | Stationing | optional |
low-point-elevation |
The elevation at the lowest point on a curve where the gradient changes from negative to positive | Real | Feet | optional |
point-of-vertical-curvature-pvc-station-10 |
The station of the point at which a tangent grade ends and the vertical curve begins. | Real | Stationing | optional |
point-of-vertical-curvature-pvc-elevation-11 |
The elevation of the point at which a tangent grade ends and the vertical curve begins. | Real | Feet | optional |
point-of-vertical-intersection-pvi-station-12 |
The station of the point where the extension of two tangent grades intersect. | Real | Stationing | optional |
point-of-vertical-intersection-pvi-elevation-13 |
The elevation of the point where the extension of two tangent grades intersect. | Real | Feet | optional |
point-of-vertical-tangency-pvt-station-14 |
The station of the point at which the vertical curve ends and the tangent grade begins. | Real | Stationing | optional |
point-of-vertical-tangency-pvt-elevation-15 |
The elevation of the point at which the vertical curve ends and the tangent grade begins. | Real | Feet | optional |
Requirements
- All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property High Point Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property High Point Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Low Point Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Low Point Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Elevation in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Station in the set Vertical Alignment Key Stations and Elevations.
- All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Elevation in the set Vertical Alignment Key Stations and Elevations.
Property Details
Point of Vertical Curvature (PVC) Station
The station of the point at which a tangent grade ends and the vertical curve begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Curvature (PVC) Elevation
The elevation of the point at which a tangent grade ends and the vertical curve begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Elevation in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Intersection (PVI) Station
The station of the point where the extension of two tangent grades intersect. Synonyms: Vertical Point of Intersection (VPI), Grade Break Point Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Intersection (PVI) Elevation
The elevation of the point where the extension of two tangent grades intersect. Synonyms: Vertical Point of Intersection (VPI), Grade Break Point Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Elevation in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Tangency (PVT) Station
The station of the point at which the vertical curve ends and the tangent grade begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Tangency (PVT) Elevation
The elevation of the point at which the vertical curve ends and the tangent grade begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Elevation in the set Vertical Alignment Key Stations and Elevations.
High Point Station
The station at the highest point on a curve where the gradient changes from positive to negative. Synonyms: Crest Requirement: All Vertical Alignment Curves may have the property High Point Station in the set Vertical Alignment Key Stations and Elevations.
High Point Elevation
The elevation at the highest point on a curve where the gradient changes from positive to negative. Synonyms: Crest Requirement: All Vertical Alignment Curves may have the property High Point Elevation in the set Vertical Alignment Key Stations and Elevations.
Low Point Station
The station at the lowest point on a curve where the gradient changes from negative to positive Synonyms: Sag Requirement: All Vertical Alignment Curves may have the property Low Point Station in the set Vertical Alignment Key Stations and Elevations.
Low Point Elevation
The elevation at the lowest point on a curve where the gradient changes from negative to positive Synonyms: Sag Requirement: All Vertical Alignment Curves may have the property Low Point Elevation in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Curvature (PVC) Station
The station of the point at which a tangent grade ends and the vertical curve begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Curvature (PVC) Elevation
The elevation of the point at which a tangent grade ends and the vertical curve begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Curvature (PVC) Elevation in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Intersection (PVI) Station
The station of the point where the extension of two tangent grades intersect. Synonyms: Vertical Point of Intersection (VPI), Grade Break Point Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Intersection (PVI) Elevation
The elevation of the point where the extension of two tangent grades intersect. Synonyms: Vertical Point of Intersection (VPI), Grade Break Point Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Intersection (PVI) Elevation in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Tangency (PVT) Station
The station of the point at which the vertical curve ends and the tangent grade begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Station in the set Vertical Alignment Key Stations and Elevations.
Point of Vertical Tangency (PVT) Elevation
The elevation of the point at which the vertical curve ends and the tangent grade begins. Reference: Illinois Department of Transportation, Bureau of Design and Environment Manual, July 2024 Revision Requirement: All Vertical Alignment Curves may have the property Point of Vertical Tangency (PVT) Elevation in the set Vertical Alignment Key Stations and Elevations.