Mode choice is the distribution of the total demand (total demand matrix) per demand stratum onto the individual traffic modes (e.g. PrT, PuT) on the basis of mode-specific skims.
There are two types of demand strata:
- Those referring directly to a demand matrix allocated to one single demand segment or several demand segments
- Those whose demand matrix is not related to any demand segment
No mode choice will be calculated for demand strata referring directly to a matrix with demand segment(s).
For demand strata whose demand matrix is not related to any demand segment it is determined per mode to which demand matrix the demand calculated for that mode has to be added during mode choice (Fundamentals: Mode choice).
1. On the toolbar, click the 
Open 'Procedure sequence' window button.
The Procedure sequence window opens.
2. To the procedure sequence, at the position of your choice, add the procedure Mode choice of the Demand model category (Setting up and starting the procedure sequence).
3. In the row of the newly inserted procedure, in the Reference object(s) column, click the button.
The Demand strata selection window opens.
4. In the Select demand model list, click the demand model the demand strata belong to.
5. In the Demand stratum selection list, select the demand strata you would like to calculate the mode choice for.
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Tip: To select multiple demand strata, hold down the Ctrl key while clicking the desired entries one by one. |
6. Confirm with OK.
The demand strata selected are listed in the Reference object(s) column.
7. Make sure the added procedure is marked. Then, in the Operations section, click the Edit button.
The Mode choice parameters window opens.
8. Make the desired changes.
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Element |
Description |
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Set any result demand matrix to 0 prior to calculation |
If this option has been selected, all demand matrices allocated to the demand strata are set to 0 prior to summing up the calculated OD demand. Note You should select the option if all pairs of demand stratum and mode allocated to the same demand matrix enter the mode choice together. |
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Apply to all DStrata |
Via this button you can apply the combination of matrices and attribute vectors settings and the utility function selected for the currently selected demand stratum to all demand strata of the demand model. |
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Key |
Unique value generated by Visum for each combination of Demand stratum and Mode. |
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Demand stratum |
The table displays important settings for each mode of a demand stratum. The table enables you to directly access all demand strata. |
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Mode |
List of all modes of the selected demand strata |
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Function type |
From a list you can select the type of utility function used for the calculation of the mode choice. Note The setting applies to all modes of the demand stratum. |
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Parameters |
a, b, c Estimated parameter values for the utility function modeling the response of travelers to distance or time conditions. The parameters can take negative values. Notes The settings apply to all modes of the demand stratum. The Function graph tab of the Choice model for <demand stratum> window shows the curve progression of the utility function due to current parameter settings. If the initial matrix contained impedance data such as distances or travel times, negative exponents need to be entered for the utility function. |
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Input demand matrix |
Button for selecting the demand matrix, which is divided on the basis of the trip distribution to the modes (Selecting matrices). |
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Input demand matrix |
Reference to the demand matrix, which - as trip distribution result - is distributed to the modes |
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Result demand matrix |
Button for selecting the demand matrix, in which the result of the mode choice for the selected demand stratum and the selected mode is saved. (Selecting matrices). |
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Result demand matrix |
Reference to the demand matrix to which the mode choice result is saved for the selected demand stratum and the selected mode. |
9. Click the 
(quick info: Other parameters) button.
The Choice model for <demand stratum> window opens. You can specify a utility function which serves for transformation of the values resulting from the combination.
10. Select the Options tab.
11. Make the desired changes.
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Element |
Description |
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Function type |
Type of the utility function for the mode choice calculation |
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Parameters |
a, b, c Estimated parameter values for the utility function modeling the response of travelers to distance or time conditions. The parameters can take negative values. |
12. Select the Function graph tab.
The Function graph tab displays the curve progression of the utility function with the currently set parameters a, b and c.
13. In the Range section, you may edit the scaling of the x axis and the y axis, if applicable.
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Element |
Description |
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X Min |
Minimum value for x-axis (negative values allowed) |
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X Max |
Maximum value for x-axis |
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Y Min |
Minimum value for y-axis (negative values allowed) |
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Y Max |
Maximum value for y-axis |
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Apply |
Click this button to use the entered values for the graph and to update the curve progression. |
14. If required, in the Parameters section, edit the parameters a, b, and c of the utility function.
15. Click the Apply button.
The entered parameter values are applied to the graph and will thus update the curve progression.
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Tip: To reset the utility function parameter values and the curve progression to default values, click the Reset button. |
16. Confirm with OK.
The Parameters: Mode choice window is displayed.
17. Click the Utility definition button.
The Utility definition for demand stratum/mode <> window opens. The utility corresponds to a result matrix which you can set for each demand stratum/mode using your own formula.
18. Enter the desired formula (Creating a matrix calculated from a formula).
19. Confirm with OK.
The Parameters: Mode choice window is displayed.
20. Click on the first column Input demand matrix.
The Select matrix window opens.
21. Choose the demand matrix, which - as trip distribution result - is distributed to the modes (Selecting matrices)
22. Confirm with OK.
23. Click on the first column Results demand matrix.
The Select matrix window opens.
24. Select the demand matrix to which the mode choice result is saved for the selected demand stratum and the selected mode (Selecting matrices)
25. Execute the procedure (Executing procedures in the procedure sequence).
Mode choice is calculated and its results are saved, per demand stratum and mode combination, to the result matrix assigned.
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Tip: You can view and edit the result matrices (Managing, showing and analyzing matrices). |
