Development of the TRANSIMS Environmental Model

U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce1997PDFTech ReportComputer modelsTravel behaviorModel atmosphereExhaust gasesEnvironmental impact analysisPolluting gasesAir pollutionChemical reactions and processesEnvironmental consequencesEnvironmental simulation modulesTransportation Analysis and SIMulation System (TRANSIMS)United StatesLos Alamos National LaboratoryWilliams, Michael D.Thayer, GarySmith, LaRonLos Alamos National LaboratoryNTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATIONNTL-ENERGY AND ENVIRONMENT-ENERGY AND ENVIRONMENTNTL-ENERGY AND ENVIRONMENT-Environment ImpactsNTL-PLANNING AND POLICY-Technology TransferNTL-REFERENCES AND DIRECTORIES-StatisticsUS Transportation CollectionThe TRansportation ANalysis and SIMulation System (TRANSIMS) is one part the multi-track Travel Model Improvement Program under joint development by the Department of Transportation, the Environmental Protection Agency, and the Department of Energy. TRANSIMS is a set of integrated analytical and simulation models and supporting data bases. The TRANSIMS methods deal with individual behavioral units and proceed through several steps to estimate travel. TRANSIMS predicts trips for individual households, residents and vehicles rather than the movement of zonal aggregates of households. The purpose of the environmental module is to translate traveler behavior into consequent air quality, energy consumption, and carbon dioxide emissions. There are four major tasks required to translate traveler behavior into environmental consequences: (1) estimate the emissions, (2) describe the atmospheric conditions into which the contaminants are emitted, (3) describe the local transport and dispersion, and (4) describe the chemical reactions that occur during transport and dispersion. The TRANSIMS environmental module will include: (1) a modal emissions module, (2) a prognostic meteorological module, (3) a Monte-Carlo kernel dispersion module, and (4) an airshed air chemistry module. It will require inputs from the TRANSIMS planner and traffic microsimulation. It will estimate emissions of relevant species and it will use large-scale meteorology and land coverage to estimate concentrations of ozone, secondary aerosols, carbon-monoxide, nitrogen-dioxide, sulfur dioxide, and respirable particular matter. It will be able to estimate both mean concentrations and fluctuations about the mean concentrations. It will be a flexible tool for "what if" questions and it can be applied to any city given appropriate topography and surface characteristics.88