Selected Joint Properties

This shows the location of the joint on the common leg of the twin intersection, measured from the origin of the first intersection in the direction denoted by the arrowheads attached to the joint. You can move the station of the joint (graphically or by entering a new value) within a small range based on where the geometry of the legs begin to change (such as where curved connections intersect).

No - The leg geometry is computed based on how you manually set properties to define the geometry of associated islands and turn lanes. Each side of the joint is designed individually without any effect on the other side of the joint.

Yes - Forces the properties of intersection legs attached to the joint to automatically match each other. Then you can edit the joint properties for one side of the twin intersection and the other side will update accordingly. The geometry is adjusted so that the ends of the legs match each other, which requires that many properties are given equal values to make the resulting geometry fit both sides.

Note: This cannot be set to for a joint between an intersection leg and a cul-de-sac.

Median

Select an option for the median:

• Fat island - Select this to specify the widths of the left and right shoulders, looking in the direction of the joint.
• Skinny left/right - Select this to specify the width of the median and the width of the left/right shoulder, looking in the direction of the joint.
• Skinny middle - (for double lane islands, which are unique to twin intersections) Select this to specify the widths of the left and right sides of the median, looking in the direction of the joint.

Note: The available options depend on the type of island that exists on the shared leg when the twin intersection is formed.
For additional information, such as on double islands, see Intersection Island Properties.

The distance across the median from outer edge to outer edge, looking in the direction of the joint.

The width of the median shoulder on the left/right side of the corridor, looking in the direction of the joint.

For double-lane islands:

• Both side slope - The crown of the median is at the road leg, and the slope is down at both sides.

For all other types of island (including None):

• Zero slope - The slope of the joint cross-section is horizontal, with a slope value=0.
• Left slope - The slope at the joint is copied from left side lane of the corridor/alignment parameters. This means that the slope at the joint and the left lane next outside are equal.
• Right slope - The slope at the joint is copied from right side lane of the corridor/alignment parameters. This means that the slope at the joint and the right lane next outside are equal.

Specify total offset value to the left/right outer edge, which includes both the lane and the shoulder.

Extra Lane

No - The computation of the turn lane geometry is free from any forced values, but it will be cut at the joint location.

Yes - The computation of the turn lane geometry is forced to match the width left/right and slope left/right values. Select Yes to add an extra lane on either side of the corridor surrounding the joint.

Width left/right - The width of turn lane at joint location.

Slope left/right - The slope of turn lane at joint location.