Add a LinkWidthAndSlope (from the Generic tab of the tool palette), set the width as half the lane and set OmitLink=Yes. In the Assembly Properties on the Construction tab check the checkbox for Use Parameter Reference and set the dropdown to the Lane Slope.

Kati Mercier, P.E. | LinkedIn | AutoCAD Civil 3D Certified Professional
Pronouns: She/Her
Co-author of "Mastering AutoCAD Civil 3D 2013"
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