Energy conservation regulations, such as fuel tares and fuel economy mandates for automobiles, are often assumed to reduce air pollution in lock step with the reduction in fuel consumption. Under the current system of tailpipe emissions regulations in the United States, this is not necessarily true. This paper uses a simple graphical analysis to illustrate the relative impact of fuel taxes and fuel economy standards on pollution levels given the current tailpipe emissions standards and an alternative emissions standard. Under current tailpipe emissions standards, increases in fuel economy would actually raise emissions, and significantly larger fuel tares would be required to achieve the same level of pollution reduction as under the proposed alternative standard. These results. confirm earlier findings that used mathematical and stochastic simulation methods to address this issue.