Demand strata

The demand stratum constitutes the basic demand object for calculating trip generation, trip distribution and mode choice. It links an activity chain with one or several person groups (in the tour-based model with exactly one person group). The pointers to activity chains and person groups in the Standard 4-step model are optional.

The correlations between the various demand objects can be display graphically as follows:

Image 49: Correlations between different demand objects

The demand object demand stratum has the following attributes.

Attribute

Description

Code (Key)

Code (any string), for example HWH Stud

ActChainCode

Activity chain code (optional)

DemandGroupCodes

Person group codes (optional)

Name

Name of demand stratum, for example student-shopping or employee+car home-shopping-home

DemandModelCode

Abbreviation of the demand model, for the respective demand stratum, for example DEFAULT

Distribution matrix number

Number of demand matrix to which the result of the distribution for this demand stratum is stored (optional)

Demand time series number

Number of demand time series for temporal distribution of demand (optional).

The following attributes describing demand strata are only relevant for EVA models.

Attribute

Description

Origin structural property codes

Origin of the structural property codes

Destination structural property codes

Destination of the structural properties codes

Balancing

Indicates the demand stratum (origin-destination type 3) in which balancing takes place

Quantity as potential

This Boolean attribute describes whether the productions or attractions of the demand stratum impact as potentials in Trip distribution/Mode choice (=1) or only have to meet the constraints (=0).

Marginal totals type origin

Marginal totals type destination

Type of marginal totals of the constraint on origin or destination side

Marginal totals min factor origin constant

Constraints max factor origin constant

Constraints min factor destination constant

Marginal totals max factor destination constant

This Boolean attribute describes, whether the lower or upper limit of the production and attraction is constant (=1) or zone-dependent (=0).

Constraints min factor origin

Constraints max factor origin

Constraints min factor destination

Constraints max factor destination

Factor for the upper or lower limit of production or attraction.