To design an alignment with a tangent polygon, click on Draw with Tangent Polygon icon. Using a tangent polygon, you can describe any combination of main elements.
After invoking the command, the Create Tangent Polygon dialog box appears.
Click OK and then in the drawing define the first point of the tangent polygon. Continue with a selection of more points to create a tangent polygon.
In the Draw lanes and widenings dialog box, you chose vehicle combination to calculate widenings. Alignment parameters such as spiral lengths and radius values are calculated based on design speed defined in alignment name Category definition.