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2.2.6 Step 6. Execute Tranplan Model
At this point, network information is stored in MapInfo as node and link tables. The Appendix describes the
procedures required for running the MapInfo Tranplan interface (exporting files and running Tranplan). Required
programs and files can be obtained from the CTRE internet site.
The output from Tranplan will be the network traffic volumes. Figure 2-21 shows the traffic volumes obtained from
running the model through Tranplan.
Figure 2–21. Model volumes for Waverly.
It is recommended that the planner compare the results of the base model volumes to actual traffic counts from the
CTAMS database. For the case study, the R-square difference between the model volume and the AADT was .90
and Figure 2-22 indicates the fit of the links.
Figure 2–22. Validation of the Waverly model.
If this calculation results in a poor R-squared value, say, less than 0.7, it is recommended that the analyst recalibrate
the model, attempt to determine the reason for the poor validation, and make changes to improve the assignment.
Changes to the model can include altering the roadway travel speeds, increasing the speeds for under-assignment
and reducing the speeds for over-assignment. The changes in speed, however, should be justified by travel patterns
in the community and the speed changes should be made in 5 mile per hour increments and remain within reason