The federal government also influences local and state planning activities by direct requirements, or "mandates." For example, the Clean Air Act amendments of 1970 require the EPA to establish certain air quality standards. To meet these standards, states are required to produce state implementation plans (SIPs). Although the states have great latitude in the precise manner in which these air quality standards are to be met, the federal legislation does force them to plan and also establishes minimum targets (levels of air quality) for which to plan. The legislation also specifies in general ways the items that state plans must contain. For example, the state plan must contain provisions for reviewing plans for the construction of facilities that might produce sufficient emissions to prevent the achievement of federally mandated air quality standards. Thus plans for a solid- waste incinerator that might push levels of air pollutants above federally mandated standards would have to be reviewed. Should a state government fail to make such a review or make the review in an inadequate manner, it might open itself up to legal action by an environmental group or other concerned parties.
The situation just described represents a particular style of regulation that is commonly used by federal and state governments. The regulating body does not tell the regulated party what to do in detail. Rather, the regulated party is told what must be achieved but is left with wide discretion concerning how to do so. Perhaps the best-known example of this regulatory style is seen in the rules pertaining to automobile fuel economy. Average mileage standards, Corporate Average Fuel Economy (CAFE), for the total fleet produced by a manufacturer were established, and fines for exceeding this standard were set. But carmakers were told nothing about what technologies to use in achieving these goals.
One advantage of this approach is that overall goals are formulated at a high level, where decision makers have an overview of "the big picture." But technical decisions are made by those who are closer to the problem and thus better informed about details. As a practical matter this style is also likely to be much more acceptable in a political system like that of the United States—one in which power is widely distributed and in which there are strong local governments and a tradition of resistance to excessive central authority.