Modeling of traffic flows and emissions

At SUEZ we use mobility flow models on a microscopic scale. SUMO (Simulation of Urban Mobility), an open source traffic simulation package, and CARUSO-TREFIC, for traffic modelling and estimation of emissions associated with road traffic.

SUMO (Simulation of Urban Mobility) 

SUMO (Simulation of Urban MObility) model is an open source, highly portable, microscopic and continuous traffic simulation package designed to handle large networks (

It allows the simulation of intermodal traffic including pedestrians. Although it is a model with a microscopic approach, it also has a module that allows creating scenarios with a mesoscopic approach.

Its characteristics include the great versatility to create scenarios from known traffic data, in addition, it also allows importing scenarios from other traffic simulation models.

SUMO is not only a traffic simulation model, but also includes a set of tools that facilitate the construction of the scenarios since, for modeling, at least a road network and a traffic demand are required.


The CARUSO-TREFIC system consists of a set of tools developed by ARIANET (SUEZ Company) for traffic modelling and estimation of emissions associated with road traffic. This tool has 2 main components. On the one hand, the CARUSO model is used to solve the problem of allocating traffic demand on a road network, while TREFIC is designed to estimate road emissions.

CARUSO (CAR Usage System Optimizator) is a traffic assignment model that simulates the demand-supply interaction. It is compatible with GIS (Geographic Information System) software for network description and modification. In addition, it has a graphical interface that facilitates network review and analysis of results. Traffic demand can be provided as a flow of vehicles or as origin/destination matrices. The results obtained from the CARUSO model can be easily coupled with TREFIC for the estimation of road emissions.

The TREFIC software (TRaffic Emission Factors Improved Calculator) is aimed at evaluating traffic emissions on a road network. Like Caruso, it allows working with GIS format both to feed the model and to analyse the results. TREFIC is able to process linear sources such as roads, but it also considers area sources such as a car park. For this purpose, TREFIC follows the COPERT methodology and its emission factors, being possible to estimate the emissions of approximately 120 pollutants. Finally, it is possible to integrate TREFIC results into an atmospheric dispersion model for air quality assessment.

What are the uses of our services in urban or industrial mobility modeling?

The first and most important, the study of emissions to the atmosphere in all the roads of the road network. But it also allows us to study scenarios of great interest, such as:

  • The study of the temporary pedestrianization of streets, e.g.: The most basic example may be the pedestrianization of a street at certain times of the day.
  • Effects studies: How does it affect traffic flows if a street is cut? E.g.: to study the affectation of a work. It could be determined in which time slots it would be more feasible to make the cut.
  • Study for the implementation of an “eco” lane (electric only, hybrids…).
  • Using smart traffic lights: Could you configure traffic lights differently based on time of day and traffic to improve flow?
  • Determination of the impact of traffic due to certain events, for example, sport events, concerts, Christmas shopping ...

Contact us

If you need this type of services related to the modeling of traffic flows and mobility, contact us.