The model decision tree in the Performance Models window determines what model is used to gauge deterioration for all road sections that meet the criteria of the branch of the decision tree. In some cases, however, the default model does not accurately predict the deterioration of a particular road section even though this section meets the criteria of the decision tree. To remedy this situation and use a model that better predicts deterioration for this road section, you associate a model with a specific road section (which overrides the default model for this road section) by following these steps:

Note: These steps assume that you know what model you wish to use in place of the default model. Of course, if you are unsure what model to use, you can experiment in the Analyze Model with different models and linear regressions (viewing the results on the Graph tab) until you find or derive the model that best fits the data. Once that model is identified, use it in step 8.
  1. Open the Section Performance window.
  2. At the top of the window, click the down arrow for the Select Column field and select the condition attribute that will be predicted by the model you wish to assign.
  3. In the upper pane, locate the road section to which the model will be assigned and select the record showing this road section to select it. After clicking the record, the lower pane will show the deterioration curves based on the default model for this road section. (The default model is shown in the Select Model field at the top of the window.)
  4. In the lower pane, right-click and select Analyze Model. The system displays the Analyze Model window with a condition versus age plot of all data points in the data set for just this road section.
  5. In the Analyze Model window, select the Models tab.
  6. In the Models tab, select the down arrow above the left pane to display the list of model types and select the model type for the model that will replace the default model. After selecting the model type, the system displays the models of this type in the left pane.
  7. In the left pane of the Models tab, locate the model you wish to assign, right-click the row showing this model, and select Move Model. The system moves the selected model to the right pane.
  8. In the right pane of the Models tab, right-click the model you just moved and select Move for Analysis. The system moves the model to the top of the pane and sets the Model Run type to 0-Selected.

  9. Right-click the top row (the row with the model you wish to use) and select Return Current Model. The system closes the Analyze Model window and assigns the selected model in place of the default model. It also redraws the curves in the lower pane of the Section Performance window utilizing the new model.

    Note: The Select Model field at the top of the window now shows the name of the model you just selected. (Also, if a section-specific model was already assigned to this road section, it will be deleted and replaced with the model you just selected.)
  10. Click the icon to save the new information.