The cost of railroad regulation: the disintegration of American agricultural markets in the interwar period
利用美国各州农产品价格数据，研究发现1920年《运输法》导致铁路监管加强，使得农业市场在两次世界大战期间解体，并估算了消费者福利损失。
This article investigates the costs of transport regulation using the example of agricultural markets in the US . Using a large database of prices by state of agricultural commodities, we find that dispersion fell for many commodities until the F irst W orld W ar. We demonstrate that this reflected changes in transport costs which in turn in the long run depended on productivity growth in railroads. The year 1920 marked a change in this relationship, however, and between the F irst and S econd W orld W ars we find considerable disintegration of agricultural markets, ultimately as a consequence of the 1920 T ransportation A ct. We argue that this benefited railroad companies in the 1920s and workers in the 1930s, and we put forward an estimate of the welfare losses for the consumers of railroad services (that is, agricultural producers and final consumers).