TL Alignment Tool
This tool aims to improve the workflow of designing alignments in Autodesk® Civil 3D®, particularly when alignment contains overlapping segments, which is usually the case with ramps.
Start by laying out the alignment segments as polylines. Create an alignment, just an initial segment is enough. Invoke the TLAlignAddPoly command and select your alignment. From that point you can start gluing polyline segments together into your main alignment using the TLAlignAddPoly command.
If a particular segment does not land where you expect it's usually due to a wrong polyline direction orientation. You can easily reverse the direction by using the TLReverseCurveDir command.