DIADEM software

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Introduction

DIADEM (Dynamic Integrated Assignment and DEmand Modelling) is software designed to enable practitioners to easily set up variable demand models that are consistent with the advice in WebTAG.

DIADEM fulfils three roles:

  • It provides a relatively simple way to link highway assignment models to a variable demand model. Currently links to CONTRAM and SATURN assignment models are supported.
  • It provides a means of achieving convergence between assignment (supply) and demand models.
  • It provides detailed convergence statistics that can be used later to estimate whether scheme benefits are robust.

Use

DIADEM is intended to extend existing highway assignment models to variable demand modelling as easily as possible. It may not be appropriate for every possible demand modelling situation. In some cases more complex demand modelling software will be required, for example:

  • when a more sophisticated treatment of main mode and submode choice is required, such as for some public transport schemes.
  • when a wider range of demand responses is required, e.g. car ownership, changes in vehicle occupancy.
  • when a wider range of generalised cost components needs to be considered, e.g. reliability, comfort, etc.

Availability

DIADEM consists of a program (diadem.exe) and associated files.

The software will run on a PC with a Pentium 133MHz chip or better. The program needs to be installed on a PC hard drive, and will only read data files from any subdirectory, as long as the user specifies to the program where the files are. For more information on the latest development in DIADEM and where to get the software go to www.diadem.org.uk.