Transport demand estimation for traffic simulations. Heuristic approach linked to vehicle counts

A transport system can be defined as the set of those components and their interactions that determine trips among different points of a territory. Its two main interacting components are: the supply system and the demand system. The first one consists of the physical (road infrastructure) and organizational (traffic structure) components that allow for trip; the second one is given by the set of users who, driven by the need to carry out activities in different places, use different modes of transport. Mathematical models for transport systems simulate demand flows, supply performance, their interactions and main effects, constituting a fundamental tool for evaluation and/or planning activities. In the literature of sector there are many models proposed for the study of transport supply and demand. Estimating the demand for mobility (expressed in terms of Origin/Destination matrix) is generally complex since it is influenced by several factors. Different methodologies, such as direct investigations in the field, or assuming more or less sophisticated models can be applied. The paper proposes an alternative approach for transport demand estimation aimed at traffic simulations; the approach is of a mixed type and integrates the modeling approach with the results of direct surveys, passing through the determination of Origin/Destination sub-matrices in terms of movement of people and vehicles. The paper proposes the methodological path taken and an application relating to an urban context.