The files that constitute the NCDOT GEOPAK Criteria Library are separated into sixteen categories and named accordingly. These categories are:

Each file contains a unique set of user-defined variables. The definitions or values of these variables dictate to the criteria file the guidelines for drawing the particular portion of the cross section for which it is responsible. Most of the criteria files are capable of multiple configurations and therefore are dependent on their variables for objective.

In order for the designers to be able to change the configuration of a particular part of the section from one station range to another, they must either be able to re-define the variables or break the project into several different runs. GEOPAK will not allow re-definition of user-variables within a criteria run, variables can be defined only once. Any subsequent definitions of a variable are ignored. Hence, a criteria file is 'locked' into the configuration defined by it's variables for the duration and length of the criteria processing run.

This criteria library is designed around a concept the author refers to as 'Virtual Variable Redefinition'. The concept is simple; we can not re-define a variable for a criteria file, but we can use more than one version of that file and it's variables.

Using three versions of the criteria file adss as an example, the designer can change the configuration of arterial standard slopes with a single run, as depicted below.

Example project:

For this example we need to change the configuration of an arterial design standard slope three times within a single run as shown in Table 1-1. This can be done by defining three versions of the variables of the adss file; and then including three versions of the adss file itself, as shown in the following input file extract.

define "AD01 DITCH WIDTH"		18	(version 1)
define "AD02 DITCH WIDTH"		0	(version 2)
define "AD03 DITCH WIDTH"		18	(version 3)

define "AD01 USE DITCH GRADE"	0	(version 1)
define "AD02 USE DITCH GRADE"	1	(version 2)
define "AD03 USE DITCH GRADE"	0	(version 3)

define "AD01 FIX CUT SLOPE"		0*	(version 1)
define "AD02 FIX CUT SLOPE"		2	(version 2)
define "AD03 FIX CUT SLOPE"		0	(version 3)	

define "AD01 FIX FILL SLOPE"		0	(version 1)
define "AD02 FIX FILL SLOPE"		3.5	(version 2)
define "AD03 FIX FILL SLOPE"		4	(version 3)


SIDE SLOPE LT where ( station >= 40+00 and station <= 53+40 )
	include adss01.cri	(version 1)

SIDE SLOPE LT where ( station >=53+60 and station <= 87+80 )
	include adss02.cri	(version 2)

SIDE SLOPE LT where ( station >= 88+00 and station <= 102+00 )
	include adss03.cri	(version 3)

The fact that the adss file is capable of handling all the configurations as described above, and more, allows the designer to specify numerous and diverse configurations using different versions of one base file name.

The whole of this criteria library embodies this concept. Various versions of each criteria file are available.