THE COMPARISON AND RANKING OF POLICIES FOR ABATING MOBILE-SOURCE EMISSIONS

Mobile-source emissions represent a large portion of all air pollutant s, especially in urban areas. While there exist many forms of vehicle emissions abatement policies and others have been proposed, formal mea sures and methods for assessing the relative efficiency and effectiven ess of these alternatives are needed. This is particularly the case gi ven the fact that the methods of externality-control most favored by e conomics (effluent or Pigouvian charges, or the direct taxing of pollu tant volume) are generally not feasible for vehicle emissions. In many cases, vehicle pollution control belongs to the realm of the search f or the 'best among the second-best' policy alternatives. In this paper the range of policy alternatives used for controlling vehicle emissio ns is reviewed. A formal methodology for assessing the relative effici ency of alternative policies is proposed, with formal measures that le nd themselves to relatively easy quantification for empirical applicat ion. It is shown that the most important components of these efficienc y assessments are the elasticity of emissions with respect to the 'tra vel activity' taxed or subsidized by an abatement policy (such as fuel taxes, vehicle taxes, subsidies for public transit, etc.), the impact of the policy upon travel consumer surplus, and the 'noisiness' or th e stochastic uncertainty of the relationship between the emissions lev el and the 'activity' being taxed or subsidized. This last factor make s the abatement policy 'noisier' and less efficient. (C) 1998 Elsevier Science Ltd. All rights reserved.