Surface Groups


Median surfaces are normally used to separate two carriageways in the design of multi-lane highways. However, they can also be used in instances such as median strips at intersections, roundabouts, etc.


The surface on either side of the centerline/median meant for traffic is defined as a carriageway.


The surface on either side of the carriageway meant for vehicle breakdown service, etc., are termed shoulder surfaces. It would also be practical to use a specific shoulder surface as a potential crash barrier zone.


The term supplementary surfaces are used as the designation for surfaces that lie beyond the shoulder but within the drainage ditch slope or embankment slope. These surfaces can be used to describe entities at the side of the road, but which are closely linked to it, such as acoustic barriers, pedestrian footpaths, ramps, and footpaths/cycle tracks. Supplementary surfaces will be utilized in full, as described in the dialog Road Surfaces. That is, they will not be broken at cuttings on the terrain surface.


Drainage ditch surfaces (at open drainage ditches) reach from the outermost surface in surface group 2 (shoulder) or the outermost extra surface, to the outermost point on the ditch.

Ditch depth: If there are additional requirements for the drainage ditch's depth below the edge of the roadbed, the drainage ditch surface can be extended beyond what is defined for ditch surfaces using the function Ditch Depth.

Ditch control (only for the Danish Version): If ditch control is employed, the drainage ditch control function examines whether the execution of the fill provides sufficient "ditch volume".

Rock Cut

The surfaces connecting the outermost ditch surface and the rock surface (in the terrain subsurface) are defined as rock cut. The possibility of having these surfaces in the road model depends on the following:

Soil Cut

The surfaces connecting the outermost ditch surface (if the outermost point of the ditch surface is located in soil formation) and the terrain surface are defined as soil cut. The possibility of having these surfaces depends on the subgrade type.


The surfaces connecting the outmost shoulder surface (or ditch surface in case of embankment ditch) and the terrain surfaces are termed as fill surfaces.