**3.4 Corridor modeling**

Before create corridors, you must have existing data, such as existing ground surfaces, alignments (centerlines), profiles (vertical alignments), and typical sections (assemblies).

All calculations should be finalized before they are applied to the corridor model. Changes in a corridor baseline alignment are not reflected in calculations. Changing the design criteria does not update the corridor model.

In **Figure 7** is shown a generic 3D Corridor model.
