assembly with superelevation and existing curb tie-in

[juanalacorina]

I am fairly new to civil 3d 2008. I am working on a 2 mile long project, it is a 2 lane road which I will be turning it into a 4 lane, I will be adding multiple left turn bays. It also has an existing curb on the right that I need to tie to, and it has a two curves with superelevation. In addition to this I will be milling and overlaying 8 to 10 feet of existing pavement. On my assembly I am using a lane from tapered median 1 for the left turn bays. However, when I try to include the overlay widen from curb my targets change which do not let me tie to my left and right allignments. this is the same for the superelevation.

Can anyone give me an idea on how I should create my assembly.

thanks, Juan