State Of The Practice Report On Mobile Source Emissions Models

Transportation engineering and transportation planning are two sides of the same coin aiming at the design of an efficient infrastructure and service to meet the growing needs for accessibility and mobility. Many well-designed transport systems that meet these needs are based on a solid understanding of human behavior. Since transportation systems

Emissions from mobile sources contribute significantly to air pollution in the United States. Such sources include cars and light- and heavy-duty trucks; diesel-powered cranes, bulldozers, and tractors; and equipment such as lawnmowers that run on small gasoline engines. The role of state versus federal government in establishing mobile-source emissions standards is an important environmental management issue. With this in mind, Congress called on EPA to arrange an independent study of the practices and procedures by which California develops separate emissions standards from the federal government and other states choose to adopt the California standards. The report provides an assessment of the scientific and technical procedures used by states to develop or adopt different emissions standards and a comparison of those policies and practices with those used by EPA. It also considers the impacts of state emissions standards on various factors including compliance costs and emissions. The report concludes that, despite the substantial progress in reducing emissions from mobile sources nationwide, more needs to be done to attain federal air-quality standards in many parts of the country. Additionally, California should continue its pioneering role in setting emissions standards for cars, trucks, and off-road equipment.

This bibliography is part of an on-going research project between the Texas Transportation Institute (TTI) and the Texas Department of Transportation (TxDOT). The bibliography has attempted to include all significant reports prepared by the Institute in support of urban transportation travel demand modeling and forecasting practice in Texas. An annotation is provided for those reports which still may be of interest to practitioners. Several reports which are now obsolete due to improvements in computer technology are included for completeness and historical interest. In addition several reports prepared by TxDOT which bear directly on travel demand modeling practice are included. The Department reports are not complete and users of this bibliography are requested to provide the Institute with copies of Department reports not presently included so that they may be included in future revisions. The bibliography is organized into six sections: trip generation, trip distribution, traffic assignment, travel surveys, air quality analysis, and overview. Reports are placed in each section according to the phase of modeling covered by the report. However, since the modeling phases are interdependent, most reports will cover aspects of more than one phase. Reports which clearly cover more than one modeling phase are placed in the overview section.