Generally speaking, when a Road is not a Road use Featurelines and Gradings/3D polylines.
Design the main Centreline roadway on one baseline then created graded lines for the rest.
Or if you really must use an alignment and corridor then use two seporate corridors, one (dummy) just for control of levels on the other alignments. Create a dynamic profile on channel lines from dummy surface.
Create a new assembly consisting of a marked point (EC) & kerb etc then add the channel line alignments as new baselines in main model corridor. PS: Note that Corridor models do not like 90 degree bends where you do not have a curve between elements so you will need to split the region at every instance of these and fill in the gaps with featurelines.
From the above workflow you can see it is more suitable to use a grading for this and create a final surface, less hassle and work in the long run.