Introduction to simulation of road traffic

Simulation of road traffic by means of digital computers is a useful tool for the analysis of traffic situations where theory does not lead to formulae or other analytical calculations which are suitable for use in practice. Like theory, sound and tested simulation models can be used to estimate the likely effects of various changes that the traffic engineer or planner may have in mind for a road system. They can also be used to gain increased understanding of traffic systems by experimenting with the models in ways that are not practicable in reality. Traffic simulation models may be stochastic or deterministic. They have been used in the formulation and validation of approximate analytical formulae, in the stochastic representation of traffic situations where the random variation cannot be analysed theoretically, and in the deterministic representation of traffic in networks. The main limitations on simulation are the degree of understanding of the system being modelled, computing resources, and the availability of data for testing of the model. Like theory, simulation depends on appropriate data about real traffic (a).