Managing Traffic and the Environment


Dynamic Simulation of Traffic and Urban Air Quality


The link between vehicular traffic and air pollution is well established and authorities in metropolitan areas throughout the world require support in managing and controlling road traffic so as to avoid exceeding pollution limits by national and international governing bodies. EU directives 96/62/ EC, 96/44/EC, and 97/11/EC reflect this trend by setting standards for traffic-related emissions and by mandating an environmental impact assessment for all major transportation projects.

TRAQS is a simulation-based decision support tool designed to help find optimal solutions to transportation issues and environmental objectives in a single integrated approach. The core of TRAQS is a simulation model covering traffic flow, emission, atmospheric dispersion, and photochemistry.

With the seamless integration of these model components, TRAQS goes directly from traffic demand and infrastructure to concentration profiles for major pollutant species with high spatial and temporal resolution. Tedious conversion of intermediate results from one model- specific format to another and complex transformations of georeferences are a thing of the past.

Recognising the range of requirements in today's environment, TRAQS offers a flexible approach that can be easily adapted to cope with different

problem areas, degrees of data availability, required precision, and computational resources.

According to their needs users may choose from:

Transportation models:

  • static traffic assignment with superimposed diurnal profile
  • mesoscopic traffic flow simulation for higher resolution and model of traffic management strategies

Air pollution models:

  • Gaussian or Eulerian dispersion models for conservative pollutants, with local field resolution
  • Photochemistry box model
  • 3-layer or multi-layer photochemistry and dispersion model

Data management:

  • Data management of all model input data in a GIS
  • GIS-style visualisation and reporting facilities
  • optional: data management of non-traffic related emission inventories
  • optional: data management of online environmental / traffic measurements

For large study areas or dense traffic networks simulation is computationally challenging. TRAQS therefore provides the key model components in both a sequential and a parallel processing variant. The parallel implementation allows simulation runs to be distributed over several processors (even over a fast LAN) as application size requires. TRAQS supports scaling further by separating user interface and simulation models: the model server can be accessed from a light-weight client with average system requirements.

With its unique combination of simulation models TRAQS can incorporate a diverse range of data sources into an overall picture of pollution levels:

  • basic geographic data for the study area, e.g. elevation model, administrative divisions, land-use, background maps
  • detailed representation of the road traffic network with a rich set of attributes supporting detailed traffic flow simulation
  • traffic demand expressed as a baseline O-D matrix and additional event-related matrices
  • models for a range of traffic management measures on different time-scales
  • meteorological observations, taken from historical records, from current measurements or from forecasts
  • emission inventories for several non-traffic related sources, e.g. household, industry, and for non- moving traffic not captured in the simulation.

A major strength of TRAQS is the model support for traffic management options, including route guidance, speed restrictions, limited access, new roads, and temporal / spatial shifts in demand. It therefore lends itself not only to assess the environ- mental impact, but also to develop transportation strategies for the sustainable cities of tomorrow.

The main system components are integrated with an interactive and graphical user interface designed for users with little or no computer experience.

Online help guides the user through the complete life-cycle of a TRAQS application project.

System Requirements

TRAQS is developed for PCs running Windows NT. The machine hosting the simulation models should be equipped with a fast Pentium-II processor, at least 128 MB RAM, and a minimum of 2 GB disk space, although actual requirements vary with the amount of model input data, e.g. historical time series of meteorological observations.

The user interface (client) can either run on the same machines as the models or separately on a Windows NT PC with at least 64 MB RAM. The integrated GIS system requires a graphics resolution of at least 1280 x 1024 with 256 simultaneous colours. Support for Unix configurations is available on request.

TRAQS is a product of the Esprit HPCN project SIMTRAP (22689)
with contributions from the projects HITERM (esprit) and ECOSIM (Telematics), funded in part by the European Commission.
ptv Software und Consulting GmbH
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Phone: +49-721-9651-200
Fax: +49-721-9651-299

Environmental Software & Services

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