Introduction
The urban
transportation system is very complex, and its performance depends on decisions
made on many levels of society whose goals and purposes may be in conflict with
each other. The process of evaluating, designing and managing such a system can
therefore not be carried out without the aid of
properly formulated models. In fact, over the past three decades, there has
been growing interest in the ability of computer applications and simulation
models for all aspects of transport operations, planning and management.
The choice of the
Computer Simulation Systems (CSS) to be used in transport studies is governed
by the objectives of the analysis as well as the available resources. A common classification method for CSS is based on the detail level
with which the incorporated models suite intends to simulate the components of
the transport system. According to this, CSS can be conveniently classified
into four categories that reconcile the differences between alternative
modelling concepts and theories, as well as between different levels of
investigation in traffic and transport studies. Starting at the most detailed
(micro-) level, we have:
·
Operational
micro-simulation models that consider the characteristics of each individual
vehicle and its interactions with other vehicles in the traffic stream;
·
Tactical network models
that are suitable for dynamic traffic effects analysis which are critical in
network simulation during medium to congested flow conditions;
·
Strategic Multi-modal transport models that are
best suited to the urban-scale analysis of travel demand and transportation
network performance;
·
Land-use/transport interaction models that
synthesise the dynamic interaction between transport provision and land-use
activities. |