Regulating Untaxable Externalities: Are Vehicle Air Pollution Standards Effective and Efficient?
Quarterly Journal of Economics · 2023 · Mark R. Jacobsen、James Sallee、Joseph Shapiro、Arthur van Benthem
中文摘要
全球共有14亿辆乘用车。政府应如何规制其空气污染排放？从技术上看，征收庇古税并不可行。大多数国家转而依赖尾气排放标准，限制新车每英里行驶的空气污染物排放量。我们评估了这些标准——美国《清洁空气法》交通运输规制的核心——及反事实政策的有效性与效率。我们发现，自1967年开始实施标准以来，美国新车每英里行驶的空气污染物排放量大幅下降，降幅超过99%。基于半个世纪数据的多种研究设计表明，尾气排放标准导致了这一降幅中的大部分。然而，尾气排放标准并不具备成本有效性，部分原因在于其未能鼓励报废占排放大部分的老旧车辆。为研究反事实政策，我们构建了车辆保有量的分析模型和量化模型。对这些模型的分析表明，收紧尾气排放标准能够提高社会福利，而提高高污染车辆的登记费可通过加速车辆报废带来更大收益，尽管这两项改革都会对不平等产生复杂影响。
Abstract
Abstract The world has 1.4 billion passenger vehicles. How should governments regulate their air pollution emissions? A Pigouvian tax is technologically infeasible. Most countries instead rely on exhaust standards that limit air pollution emissions per mile for new vehicles. We assess the effectiveness and efficiency of these standards, which are the centerpiece of U.S. Clean Air Act regulation of transportation, and counterfactual policies. We show that the air pollution emissions per mile of new U.S. vehicles has fallen spectacularly, by over 99%, since standards began in 1967. Several research designs with a half century of data suggest that exhaust standards have caused most of this decline. Yet exhaust standards are not cost-effective in part because they fail to encourage scrap of older vehicles, which account for the majority of emissions. To study counterfactual policies, we develop an analytical and a quantitative model of the vehicle fleet. Analysis of these models suggests that tighter exhaust standards increase social welfare and increasing registration fees on dirty vehicles yields even larger gains by accelerating scrap, although both reforms have complex effects on inequality.