LaneFromTaperedMedian1

This subassembly inserts one or more travel lanes outward at a constant grade from an alignment that defines the edge of a median that tapers to allow for left-turn lanes.

The alignment defining the edge of the median may at times be either not present (Case 1), outside the roadway centerline (Case 2), or inside of the centerline (Case 3). To use this subassembly you should have separate alignments defining the left and right edges of the median. It may be necessary to define separate corridor model regions for each individual median.

Attachment

The attachment point is at the location where the inside edge-of-traveled-way would be if there was no median. This is typically at the assembly baseline, but may be at any marker point on the assembly.

Input Parameters

Note: All dimensions are in meters or feet unless otherwise noted. All slopes are in run-over-rise form (for example, 4 : 1) unless indicated as a percent slope with a “%” sign.

Parameter	Description	Type	Default
Side	Specifies which side to place the subassembly	Left / Right	Right
Lane Width	Width of the lane for the condition where there is no median; that is, from the attachment point to the outside edge-of-traveled-way.	Numeric	3.6 m 12.0 ft
Use Superelevation Slope	Specifies to use superelevation slope	Selection list	No
Slope Direction	Specifies whether the shape slopes away from the crown or towards the crown	Selection list	Away from Crown
Default Slope	Specifies default slope for the lane, if superelevation slope is not specified.	Numeric, positive	- 2.0%
Inside Adjustment	Used if the Median Edge alignment is at a fixed offset from the actual edge-of-traveled-way (for example, at the back of curb). Adjusts the calculated Lane Width to account for the offset (see diagram).	Numeric, positive	0.0
Outside Adjustment	Used if the Outside Lane Width alignment is at a fixed offset from the actual edge-of-traveled-way (for example, at the back of curb). Adjusts the calculated Lane Width to account for the offset (see diagram).	Numeric, positive	0.0
Pave1 Depth	Depth between finish grade and Pave1 (zero to omit)	Numeric, non-negative	0.025 m 0.083 ft
Pave2 Depth	Depth between Pave1 and Pave2 (zero to omit)	Numeric, non-negative	0.025 m 0.083 ft
Base Depth	Depth between Pave1 and Base (zero to omit)	Numeric, non-negative	0.100 m 0.333 ft
Subbase Depth	Depth of the Subbase layer at the attachment point (zero to omit)	Numeric, non-negative	0.300 m 1.0 ft

Target Parameters

This section lists the parameters in this subassembly that can be mapped to one or more target objects. For more information, see To Specify Corridor Targets.

Parameter	Description	Status
Median Edge	May be used to shift the starting offset of the lane to follow an edge-of-median alignment. The following object types can be used as targets for specifying this: alignments, polylines, feature lines, or survey figures.	Optional
Lane Width	May be used to shift the ending offset of the lane to follow an edge-of-lane alignment. The following object types can be used as targets for specifying the width: alignments, polylines, feature lines, or survey figures.	Optional
Outside Elevation	May be used to override the normal lane slope and tie the outer edge of the travel lane to the elevation of a profile. The following object types can be used as targets for specifying the elevation: profiles, 3D polylines, feature lines, or survey figures.	Optional

Output Parameters

Parameter	Description	Type
Lane Width	Width of the lane	Numeric
Lane %Slope	% slope of the lane	Numeric

Behavior

Outside Edge-of-Traveled-Way: The width to the outside edge-of-traveled-way can be defined by a fixed numeric width, or an alignment can be used to override the width. The elevation is determined by applying the specified slope for the width of the lane, unless an Outside Elevation profile is given. In that case, the outside edge elevation is tied to the profile, and the slope is adjusted.

The location of the inside edge-of-traveled-way is calculated based on the three cases shown in the preceding diagram. If no Median Edge alignment is given, or the given one is not found at a station, the inside edge is held at the attachment point (Case 1). If a Median Edge alignment is given, and that alignment is outside the lane’s attachment point, the inside edge is shifted outward from the attachment point at lane slope (Case 2). If the Median Edge alignment is inside the lane’s attachment point, the inside edge is shifted inward from the attachment point at the lane slope (Case 3).

Inside and Outside Adjustments: The Inside Adjustment and Outside Adjustment parameters are provided in case the alignment used for the median edge or lane edge is at a fixed offset from the actual edge-of-traveled-way. For example, the alignment being used for the Median Edge may be at the back-of-curb instead of at the pavement edge. In this case the Inside Adjustment parameter should be set to the width of the curb.

Layout Mode Operation

In layout mode, this subassembly displays the links comprising the lane for the given width and slope. If a superelevation slope is given (LI or LO), the links are displayed at a slope of -2%.

Point, Link, and Shape Codes

The following table lists the point, link, and shape codes for this subassembly that have codes assigned to them. Point, link, or shape codes for this subassembly that do not have codes assigned are not included in this table.

Point, Link, or Shape	Code	Description
P1, P2	ETW	Edges of lane on finish grade
P3, P4	ETW_Pave1	Edges of lane on Pave1 layer
P5, P6	ETW_Pave2	Edges of lane on Pave2 layer
P7, P8	ETW_Base	Edges of lane on Base layer
P9, P10	ETW _Sub	Edges of lane on Subbase layer
L1	Top, Pave	Finish grade surface
L2	Pave1	Pave1 surface
L3	Pave2	Pave2 surface
L4	Base	Base surface
L5	SubBase, Datum	Subbase surface
S1	Pave1	Area between finish grade and Pave1
S2	Pave2	Area between Pave1 and Pave2
S3	Base	Area between Pave2 and Base
S4	SubBase	Area between Base and Subbase