One of the main uses of Visum is modeling transport demand. Demand modeling deals with traffic forecasts. The most common travel forecasts analyze the daily travel behavior of people. These forecasts provide answers to the questions, when, how often, where and how do people travel.
Visum provides the following procedures for demand modeling:
- Standard 4-step model (Standard 4-step model in two variants)
- EVA (EVA (passenger demand model))
- Tour-based model (Activity chain based model (tour-based model))
- Tour-based freight model (Tour-based freight model)
- Activity-based demand model (Activity-based model (ABM))
The result of these procedures are matrices, which contain trips between the origin and destination zones of the network. These matrices are assigned to one or more demand segments. Assignment takes place on the basis of demand segments (User model PrT and User model PuT).
It is not mandatory to create a separate demand model in Visum, which calculates the matrices for the assignment. You can also use and assign matrices from external sources. Therefore, a complete demand description in Visum (that of course allows you to calculate an assignment) first only consists of the following elements:
- the transport demand in form of a matrix (Matrices)
- temporal distribution of the transport demand by specifying a time series (Time series). Specifying a time series is, however, only necessary for dynamic PrT assignments and PuT assignments. The demand distribution is ignored in the case of static PrT assignments.
- the allocation of matrices to one or more demand segments (Demand segments)
There are several demand objects that allow you to display the demand within the Visum data model (Demand objects). Which of these demand objects are applied in your model, depends on the type of demand modeling in your network.
