For demand calculation by means of EVA-P demand models you have to define so-called constraints by demand stratum. The steps EVA trip generation and EVA distribution/mode choice will consider these constraints (Fundamentals: EVA trip generation).
1. On the Demand menu, click Demand models.
The Demand models window opens.
2. In the Select demand model list, click the demand model of your choice.
3. Select the Constraints tab.
4. Make the desired changes.
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Note: For a better overview, the columns of the tab are divided by vertical separators into basic attributes, origin attributes, and destination attributes. |
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Element |
Description |
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DStrataCode |
Short name of the demand stratum |
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OD type |
OD type of the corresponding activity pair of the demand stratum (Properties and options of activity pairs) |
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Balancing |
Via this option you select the demand strata the balancing of constraints is to be performed for. Note You can only select this option for a demand stratum with OD type 3. |
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Constraint origin |
Type of constraint on origin side. For selection, use the selection list. Hard CF OMin = CF OMax = 1. Thus, the production rate needs to be fully considered for trip distribution. Soft CF OMin = 0, CF OMax ≥ 1 for a constant constraint factor. If CF DMax is not constant, but zone-dependent, the zone attribute value is applied. Elastic CF OMin ≥ 0 and CF OMax ≥ 0 for constant constraint factors. If CF OMax or CF DMax is not constant, but zone-dependent, the zone attribute value is applied. Open CF OMin = 0 and CF OMax is not limited. Note The constraint type of demand strata with OD type 1 is always hard on the origin side. |
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CF OMin constant |
Note This option is only provided for the Elastic constraint type. |
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CF OMin |
Factor for the lower limit of productions. Note You can edit this factor value according to the constraint type and the constant factor settings (Editing non-constant constraint factors values). |
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CF OMax constant |
This option is only provided for the constraint types Weak and Elastic. |
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CF OMax |
Factor for the upper limit of productions. Note You can edit this factor value according to the constraint type and the constant factor settings (Editing non-constant constraint factors values). |
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Constraint destination |
Type of constraint on destination side. For selection, use the selection list. Hard CF DMin = CF DMax = 1. Thus, the attractions need to be fully considered for trip distribution. Soft CF DMin = 0, CF DMax ≥ 1 for a constant constraint factor. If CF DMax is not constant, but zone-dependent, the zone attribute value is applied. Elastic CF DMin ≥ 0 and CF DMax ≥ 0 for constant constraint factors. If CF DMin or CF DMax is not constant, i.e. zone-dependent, the zone attribute value is applied. Open CF DMin = 0 and CF DMax is not limited. Note The constraint type of demand strata with OD type 2 is always hard on the destination side. |
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CF DMin constant |
Note This option is only provided for the Elastic constraint type. |
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CF DMin |
Factor for the lower limit of destination demand. Note You can edit this factor value according to the constraint type and the constant factor settings (Editing non-constant constraint factors values). |
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CF DMax is constant |
This option is only provided for the constraint types Weak and Elastic. |
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CF DMax |
Factor for the upper limit of the attractions. Note You can edit this factor value according to the constraint type and the constant factor settings (Editing non-constant constraint factors values). |
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Quantity as potential |
Note This option is relevant only if hard constraints have been set for just one side - either for productions or for attractions. |
If this option has been selected, the factor for the lower limit of the origin rate is identical for all zones (constant).
If this option has not been selected, the factor for the lower limit differs by zone (from zone attribute).5. Confirm with OK.
The constraints are stored for the demand strata of the selected demand model.
