MICROSIMULATION MODELS: THEY CAN BE SEEN BUT CAN THEY BE BELIEVED?

This article reports interviews with several transport model developers and users about the latest trends in transport models. The world of transport modelling is changing. Greater computer and data processing power has increased the potential for using microscopic simulation methods, which can evaluate adaptive control systems, selective priorities, and other Intelligent Transport System (ITS) applications. Thus micro transport models can solve many problems out of reach of macro transport models. Microsimulation traces the passage of individual vehicles through a road network, displayed on a screen, as they change lane, speed up, or slow down according to circumstances. It can model drivers' reactions, and show how queues build up in congested traffic. Input flows for the model come from origin-destination data. Data from the individual vehicle movements can be aggregated, to calculate journey times, delays, and queues, and identify the most congested locations. The range of available microsimulation models is also expanding rapidly. A recent EU-funded study of models, led by the Institute for Transport Studies at Leeds University, resulted in the scope of several models to be enhanced, to cover bus priority systems and adaptive traffic signal control, for example. The article describes various examples of models.