Transport Models
Transport models
'Conventional' (or classical four stage) transport models and their components, are the the most common models used for transport planning purposes.
Transport models describe current levels of demand, replicate current movement patterns and define system capacities and thereby provide a detailed representation of a transport system for analysis and forecasting purposes.
Model Stages
Transport models typically have up to four stages, namely:
- Stage 1 Trip generation and attraction: The amount of travel generated by or attracted to different land use type zones.
- Stage 2 Trip distribution: The amount of movement between each zone pair.
- Stage 3 Mode choice: The use of modes for movement between zones (not undertaken for 3 stage models)
- Stage 4 Trip assignment: The exact routes or services within the network used for inter-zonal movement.
Model Types
Specific types of transport model include:
- Transport models (three or four stage) EMME, TRACKS, VISUM, CUBE, TRANSCAD, TRANSIM
- Assignment models (single stage) SATURN, CONTRAM, VISSIM, AIMSUN, PARAMICS, SISTM
- Operational models (traffic engineering) TRANSYT, SIDRA, LINSIG, OSCADY, ARCADY, PICADY, Operational spreadsheet models
The main use of 'conventional' transport modelling is in the evaluation of transport network improvement options. However, for some test purposes, especially those involving significant changes to current policies and strategies, transport models are limited and additional techniques, such as simplified modelling, may be required.