Technical data

Working with Alignments

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To create spirals, use the Spiral commands on the Lines/Curves menu.

If you know the intended speed for the alignment, then you can draw

spirals using an AASHTO or user-defined speed table, which

automatically calculates superelevation information for the alignment.

Key Concepts

■

If you use the Lines/Curves menu commands instead of PLINE or

LINE, then the lines, curves, and spirals are drawn tangent to their

adjacent object.

■

You can define more than one alignment from the same alignment

geometry.

To create alignment geometry

Steps

Use

to look up

Create a layer on which the alignment centerline is

to be drawn. Use a name like “CL” for Centerline.

Creating and Naming

Layers

Use one of the line drawing options in the

Lines/Curves

menu.

Draw a Line Tangent to a

Line or Curve

To add curves, you can use the curve commands

in the

Lines/Curves menu. You can add a curve

between two tangents, off the end of a tangent,

and more. These options ensure that the curve is

drawn tangent to the selected lines.

Overview of Drawing Curves

If you need a spiral, then use one of the spiral

commands in the Lines/Curves menu.

Overview of Drawing Spirals