Restricting the Trash Trade
建立城市固体垃圾跨州市场的经济模型，评估限制垃圾流动政策（如进口禁令、数量限制、附加费）的潜在经济影响，分析这些政策如何影响垃圾处理设施所有者和使用者，以及不同区域间的差异。
In early 1999, the mayor of New York City announced a plan for exporting most of his city’s waste (about 13,000 tons per day) to other states. The responses escalated an already growing war of words about interstate waste shipments. A Pennsylvania state legislator bluntly called the mayor’s plan “irresponsible,” and the governor of New Jersey labeled it “a direct assault” on her state. A spokesperson for New York City’s Department of Sanitation coolly staked out the City’s position: “You can’t stop interstate commerce. ... If Virginia is the least expensive place to deliver this solid waste, then that is where it is going to go.” The response was swift: various legislators joined environmental activists to send 50 pounds of trash to the mayor’s office. Led by the governor’s efforts, the Virginia General Assembly subsequently responded with proposed legislation to restrict significantly imports of waste (see R. H. Melton, 1998). Virginia’s legislative proposal came on the heels of numerous similar proposals by other states to which large shipments of waste are transported. Interstate shipments of waste involve almost the entire nation (47 states export waste, and 44 states import waste) and represent nearly $1 billion annually in disposal and transportation fees. Since the early 1990’s, these shipments have increased by more than 30 percent. As officials in importing states have sought to curb these flows, the U.S. Supreme Court has repeatedly struck down their proposed restrictions as violations of the Interstate Commerce Clause. In response, the Congress has advanced proposals to exempt waste from jurisdiction of that clause. To date, however, very little is known about the positive and normative effects of the various proposals to restrict municipal solid-waste transshipments. How are the effects of restrictions likely to be distributed among the owners of waste-disposal facilities and the users of these services? Given that the Northeast is a net exporter and the Midwest is a net importer of waste, are the effects likely to differ among regions of the country? In this paper we model the interstate market for municipal solid waste and evaluate the potential economic effects of public policies proposed to restrict waste flows. These restrictions include local and state requirements stipulating where waste must be landfilled, prohibitions on the import or export of waste across state boundaries, quantitative limits on these flows, and extra fees levied on imported waste. To our knowledge, this research is the first to evaluate these proposals quantitatively. We develop both a conceptual and a computable economic model of the use over time of spatially differentiated resources, characteristics which well describe the nation’s landfill facilities (landfills, rather than recycling or other disposal options, are the dominant destination of most interstate shipments). The model characterizes the efficient intertemporal allocation of spatially distributed waste-disposal capacity among users who are also spatially distributed. In addition,