ON THE RELATION BETWEEN USERS' BENEFITS AND THE ECONOMIC EFFECTS OF TRANSPORTATION ACTIVITIES
重新审视交通改善带来的用户剩余与经济效益之间的关系，发现竞争性生产环境下两者相等，而垄断条件下用户剩余可能无法准确反映经济收益，并探讨了混合条件及最终产品需求弹性的作用。
ABSTRACT. The addition of output variation benefits to the users' surplus generated by transportation improvements has been subject to debate, and no agreement has been reached. In this paper, the problem is restated at the level of the origins of transportation demand, which can be derived from the information provided by the economic activity. It is shown that a competitive productive environment makes the transportation consumers' surplus exactly equal to the net economic benefits provoked in the products' markets; however, when monopolistic production prevails, the users' surplus may not reflect the benefits to the economy with accuracy. Mixed conditions are also explored and the role of final products' demand elasticity is highlighted. Different styles of welfare analysis are recommended for different market conditions.