The Allowable Growth interface allows the privileged user to edit and maintain percentage factors for the maximum allowable change in volume between collection years. These factors are used by the system to determine the amount allowed in the calculated percentage change between the current volume count and the volume count that was used the previous year for the same station. If the calculated percentage is greater than the percentage set in this interface, an error message will be generated so that the user knows the new count is possibly out of range. When the user selects the Allowable Growth icon (), this interface will appear:

There are three actions available in this interface: Edit Range, Add Range, and Delete Range. To edit a range, the user can click on the desired row in the table. Then, the row will be highlighted and its AADT Value and Allowable % Growth fields will be editable. The user can enter values into the textboxes here and click "Save Changes" to solidify the new values. To add a range, the "Add Range" link can be selected; this will add a blank row to the bottom of the table. The user can enter values here to create a new range, then click "Save Changes." To delete a range, the user can select a table row's checkbox and click the "Delete Selected" link. This will remove the entry from the table.

If at any point the user wishes to revert the table to its last saved state, the "Discard Changes" button can be utilized.