3.2.5 Applying Model Files of All Three Trip Purposes
Once model files are created for productions and attractions of all three trip purposes, apply them to generate estimated trip ends. Select Planning / Trip Production / Apply a Model. Under Open Model File, select the model file (e.g., HBW_P). Click OK. In the Forecast dialog box, enter:
- Apply to: TAZ
- Results in: FHBW_P
- Using: All Records
Verify that the model is correctly specified; if not, change it in the boxes following Settings.
- Procedure: Regression
Click OK. Note the values being filLED in the field of FHBW_P in the TAZ dataview. Follow the same procedure to generate values for FHBW_A, FHBO_P, FHBO_A, FNHB_P, and FNHB_A.
In the Results Summary dialog box, click on Show Report to open a text file tcw_rep.txt. This file contains the parameters of the regression model that was just applied. This file can be closed without saving since this information is in the model file itself. Also close the Results Summary dialog box.
3.2.6 Summary of Trip Production and Attraction Models
Provide a summary table comparing the estimated values of all three trip purposes. Compute a "goodness-of-fit" measure to show how close the estimated values are to the observed values in Table 3.
3.3 Trip Balancing
In trip generation, because trip productions and attractions values are estimated separately, the total number of trip productions will not typically equal the total for attractions. A difference would violate the requirements for trip distribution analysis (i.e., the subsequent stage). The trips must be "balanced" so
