EMISSIONS OF CRITERIA POLLUTANTS, TOXIC AIR POLLUTANTS AND GREENHOUSE GASES FROM THE USE OF ALTERNATIVE TRANSPORTATION MODES AND FUELS.

Policy makers in transportation often make investment decisions involving hundreds of millions of dollars. Typically they evaluate a wide range of alternatives -- from expanding highway capacity to managing existing demand to building a new rail line -- with respect to a broad array of seemingly incommensurable criteria. In theory, a policy maker can evaluate alternatives by cost-benefit analysis, in which one quantifies and monetizes all of the costs and benefits to society, and picks the alternative that yields the greatest net present-value of benefits. In this report, we quantify a key component of the social-cost part of cost-benefit analysis: emissions of air pollutants from different transportation modes.