The World Is Not Yet Flat: Transport Costs Matter!
利用微观商品流和工厂数据，研究发现卡车运输成本上升显著降低了加拿大制造业的地理集中度，解释了1992-2008年间约20%的集中度下降。
The paper provides evidence of the \n effects of changes in transport costs on the geographic \n concentration of industries. The analysis uses micro-level \n commodity flow data and micro-geographic plant-level data to \n construct industry-specific ad valorem trucking rates and \n continuous measures of geographic concentration. The \n findings show that, controlling for international trade \n exposure and input-output links, increasing trucking rates \n are significantly associated with declining geographic \n concentration. The effect is large: changes in trucking \n rates explain around 20 percent of the observed decline in \n geographic concentration of Canadian manufacturing \n industries between 1992 and 2008.