Air Pollution Considerations in Traffic Planning and Engineering

IN T R O D U C T IO N In recent years there has been a growing concern about the rapidly deteriorating environment in the urban areas of this country in terms of air, water, and noise pollution. Automobile transportation has been found to be a significant factor in the deterioration of the urban environment, particularly in regard to air pollution. In general, con­ sidering the total tonnage of pollutants in urban areas, about 60 percent is attributed to motor vehicles. In the last several years measures have been taken by the federal, state, and local governments to curb air pollution. The Clean Air Act of 1970 authorized the federal government to promulgate air quality standards and to require states to adopt implementation plans in meeting these standards. As automobile transportation is closely associated with the problem of urban air pollution, a major part of the strategies for the improvement of air quality is related to this source of pollution. A great effort has been made to reduce pollution emitted by the automobile by requiring new automobiles to be fitted with air pollution control devices. In addition, a significant part of air pollution control strategy can be achieved through effective traffic engineering measures. Consequently, it is important that a traffic engineering decision be made not only on the basis of cost savings, increased safety, and im­ proved traffic performance, but also on such aspects as reduced energy requirements and improved quality of environment. In this paper a brief discussion is presented on the overall considerations of air pollu­ tion as they relate to traffic planning and engineering.