In AutoCAD Civil 3D, the Intersection Corridor Type property identifies the type of grading that will be applied to roads in an intersection object.
There are two types of intersection grading options that are available with AutoCAD Civil 3D intersection objects: Primary Road Crown Maintained and All Crowns Maintained. You must specify this type when you create the intersection, on the General page of the Create Intersection wizard.
For existing intersections, the intersection corridor type is displayed on the Intersection Details tab of the Intersection Properties dialog box, in the Intersection Quadrants section. You can set the creation default for this option on the Edit Command Settings - CreateIntersection dialog box.
Once the intersection is created, you cannot change the value of the Intersection Corridor Type property. If you do want to change this option after the intersection object is created, you must delete the intersection object, and create a new one with the desired Intersection Corridor Type.
In this type of intersection, the crown of the primary road is maintained, while the crown (profile) of the secondary road is adjusted to match the edge of the primary road and the intersection point. The crown (profile and edges) of the primary road are not affected.
The following conceptual graphic is displayed on the wizard dialog when you select this option:
This represents how the grading occurs for the intersection object.
In this type of intersection, the profile of the side road is adjusted to match the main road elevation at the intersection point. The main road profile is not affected. The edges are blended together along the curb returns (via the curb return profiles).
The following conceptual graphic is displayed on the wizard dialog when you select this option:
