Calculating ABM long-term location choices

The procedure calculates the long-term location choices of persons for certain activities (Fundamentals: ABM long-term location choices). As a rule, these are the destinations of compulsory activities such as work and school.

1.  On the toolbar, click the Open 'Procedure sequence' window button.

The Procedure sequence window opens.

2.  Add the ABM long-term location choices procedure of the Demand model category to the procedure sequence (Setting up and starting the procedure sequence).

3.  Make sure the added procedure is marked. Then, in the Operations section, click the Edit button.

4.  Make the desired changes on the Basis page.

Element

Description

General settings

Mode set

Select the number of selectable modes.

Time reference

Start of the activity

Enter the typical start time of the activity execution in seconds (0 means 00:00 on the first day of the AP). The start time can be set individually for each person or uniformly for all persons.

Duration of the activity

Enter the typical duration of the activity in seconds.

Individual preferences

Individual preferences are generated by Visum whenever they are needed for the calculation. However, if you want to create the individual preferences reproducibly, you must have them recalculated after model adjustments. The recalculation is only recommended for the demand calculation of the base case. A recalculation for a scenario destroys the stability function of the ABM Nested Demand.

Random seed

If the settings are otherwise unchanged, a different random seed will generate different individual preferences and therefore a different result.

Recalculate individual preferences

If the option has been selected, the individual preferences are recalculated.

5.  Make the desired changes on the ABM person groups page.

Element

Description

Person groups correspond to the demand strata in aggregated demand models (see also ABM tour groups in (Calculate ABM Nested Demand)). The person groups defined here are referenced in all other tabs.

In the Person filter column, you can insert a freely editable formula expression for each person group that describes the respective group.

Note

You can copy selected person groups to the clipboard via the shortcut menu.

6.  Make the desired changes on the Shortest path searches page.

Skims for determining the utility can be determined on the basis of shortest path searches. Parameters for these shortest path searches and the resulting travel times are defined here.

Element

Description

Allow internal traffic

If this option is selected, shortest paths within a location are permitted.

If the option is not selected, there is generally no shortest path within a location, regardless of whether the shortest path is included in the utility definition or not.

Parameters per PuT mode

TSys for origin and destination walk path

Transportation system for the walk path from locations to stop areas and vice versa.

Maximum walk path time

The shortest path search only takes into account those stop areas that can be reached within the maximum walk path time.

Impedance factor for walk path time

For public transport paths, the impedance to be minimized in the shortest path search also includes the origin and destination walk paths to and from the stop areas. This is included in the impedance with the specified factor.

Impedance criterion and travel time for location-based shortest path searches

Impedance attributes and attributes for the travel time are set for private transport modes, impedance matrices and matrices for the travel time are set for public transport modes.

Impedance attribute

In the private transport shortest path search, the shortest path search is searched for in relation to this impedance attribute. The same code must be available for the three path objects links, turns, and main turns (if available in the network). User-defined attributes are often used here (as in the ABM Nested Demand example of use).

Note

Restricted traffic have a special status: The impedance attribute may or may not exist for restricted traffic areas.

Dynamic (i.e. time-dependent) attributes are indicated by an empty bracket. Only user-defined attributes that have analysis time intervals as a subattribute are permitted.

Impedance matrix

A stop area matrix is provided for the public transport shortest path search. Time-dependent matrices are defined by matrix conditions such as [TOTIME]=CONTEXT[TOTIME].

7.  Make the desired changes on the Base utility page.

Note: The utility is the sum of the rows. The value per row is in turn multiplied by the columns. The two tables are synchronized; the right-hand table shows the utility of the combination of person group and mode marked in the left-hand table. You can use the symbols above the table on the right to insert additional utilities for each row.

Element

Description

Person factor

Formula attribute of the person for whom a choice is made, or a derived relation.

Notes

The attribute value is evaluated at the beginning of the calculation. All attributes or relations that only become available in the course of the calculation must not be selected, as they are not yet known at the beginning.

Zone utility

Matrix formula for the zone utility

As is usual with matrix formulas, matrix, zone, and mode attributes can also be used via the context operator (e.g. CONTEXT[MODE\BETA]). Additional relations are not permitted, even if they are provided in the attribute selection window. The same applies to dynamic attributes.

Time-dependent matrices are defined by matrix conditions such as [TOTIME]=CONTEXT[TOTIME].

If a zone utility is defined, all locations must be allocated to a zone (Properties and options of locations).

Location utility

Utility at the level of location relations

In private transport, this is the result of a shortest path search between the participating locations. In public transport, the walk time from the location to the stop area or from the stop area to the location can also be selected.

Shortest PrT path attribute

Attribute of the shortest path search (if selected accordingly in the location utility)

It must be available for the three path objects links, turns, and main turns (if available in the network). Restricted traffic areas have a special position: The attribute does not have to be available for restricted traffic areas and attributes of the restricted traffic areas do not have to be available for the other path objects.

Dynamic (i.e. time-dependent) attributes are indicated by an empty bracket. Only user-defined attributes that have analysis time intervals as a subattribute are permitted.

Note

Make sure that all skims are specified in the desired unit. Typically, the unit minutes is used. If the shortest path attribute is defined in seconds, the skims must be multiplied by 1/60 accordingly.

Matrix for shortest PuT path

Stop area matrix

Dynamic output matrices are referenced using the context operator, as with the zone utility.

Note: Using the symbols, you can easily export or import the utility definitions via the clipboard, for example to/from Microsoft ExcelTM.

8.  Make the desired changes on the Scaling parameters page.

Element

Description

Location choice lambda / Mode choice lambda

Set the desired values for each person group.

Note

If the location choice lambda is set higher than the mode choice lambda, a warning is issued. You can calculate with such lambda combinations, but according to common discrete choice theory, this does not correspond to a regular choice-making process and can lead to inconsistent choices.

9.  Confirm with OK.

10.  Execute the procedure.

The locations are calculated. The results can be found in the persons list under long-term choice keys.