MOBILE6 Evaluation and Impact (TTI-2002-17)

The U.S. Environmental Protection Agency (EPA) highway vehicle emission factor model provides average in?use fleet emissions factors for three criteria pollutants: volatile organic compounds (VOC), carbon monoxide (CO), and oxides of nitrogen (NOx). The model generates highway mobile source emissions inventories, motor vehicle emission budgets, and control strategies for State Implementation Plans (SIPS) under the Federal Clean Air Act, and develops environmental impact statements under the National Environmental Policy Act. Periodically, the EPA updates its MOBILE model based on more recent testing data and federal regulations. MOBILE6, the newest model, incorporates updated basic emissions rates, off-cycle driving cycles, new fuel effects, separation of start and running emissions, facility-based and hourly emissions factors, updated fleet information, and vehicle characterization. It also includes impacts of recently promulgated regulations not included in MOBILE5 and provides improved input and output features. These changes may be characterized as input development and program conversion. This work order is part of a five-part strategy for the implementation of MOBILE6. The five parts are: (1) administrative coordination, (2) input data development, (3) program conversion, (4) model impact on emissions rates, and (5) actual application to areas in Texas. This work order addresses program conversion and the development of input data, which refers to computer code changes in the Texas Mobile Source Emissions Estimation Software. There are six tasks. Documentation of the first five tasks, which are most closely related to the actual conversation and modification of the Texas software, is in the form of a user's guide for the revised Texas Mobilr Source Emissions Estimation Software. This technical note documents the sixth task, and evaluation of MOBILE6.