About Creating Corridors
You can use two methods to create a corridor: using the Create Corridor command or the Create Simple Corridor command.
About Corner Cleanup for Corridors
Where corridor tangents intersect at a corner, and where the corridor is created at a fixed width, the inner and outer corners of corridors are cleaned up automatically. In other situations, such as when the corridor is created at a non-fixed width (such as when daylighting to a surface) or when there are curves in the corridor baseline, you may need to clean up the corners by extracting a dynamic feature line from the corridor and then grading from the feature line.