Hi Eugene,
I think your roads data should contains some special flag like road level for this status.
For example, we have a road looks go intersection another road only by coordinates, but in fact it go on a bridge and the other road go through the aperture of bridge, so in this point your data need tell you this situation by some feature or flag.
And you should want to write custom code to handle this situation. When you build your routing index, you can handle the special situations in event.
Regards,
Don