Traffic microsimulation describes the process of creating a virtual model of a city's transportation infrastructure in order to simulate the interactions of road traffic, and other forms of transportation, in microscopic detail. This involves treating each vehicle, bus, train, tram, cyclist, pedestrian etc. in the model as a unique entity with its own goals and behavioural characteristics; each possessing the ability to interact with other entities in the model.
Traffic microsimulation computer models capture the interactions of real world road traffic through a series of complex algorithms describing car following, lane changing, gap acceptance, and spatial collision detection. In addition, free form pedestrian movement is replicated using agent based spatially aware models allowing road traffic to interact with pedestrians as they do in the real world.
Traffic microsimulation models are quickly becoming the defacto standard for the evaluation and development of road traffic management and control systems worldwide.
Traditional (non simulation) models provide a simplified aggregated representation of traffic, typically expressed in terms of total flows per hour. In such models, all vehicles of a particular group obey the same rules or behaviour. This simplistic approach does not allow the accurate modeling of some of today's more common transport planning / traffic engineering applications i.e. intelligent transportation systems, complex junctions, shockwaves, incidents and breakdowns, HOV / HOT lanes, freeway management plans and actuated signal control. Only traffic microscopic simulation is capable of replicating the complex behaviours exhibited in these scenarios that ultimately affect road network performance and the quality of an urban space.