The Effects of Roads on Trade and Migration: Evidence from a Planned Capital City
利用巴西高速公路的准外生冲击，研究发现道路系统使福利提高2.8%，其中76%来自贸易成本降低，24%来自移民成本降低，且福利改善存在空间异质性。
A large body of literature studies how infrastructure facilitates trade. We ask whether infrastructure also facilitates migration. Using a general equilibrium trade model and rich spatial data, we study the impact of a large, plausibly exogenous shock to highways in Brazil on both goods and labor markets. We find the highway system increased welfare by 2.8 percent, of which 76 percent was due to reduced trade costs and 24 percent to reduced migration costs. An implication of costly migration is spatial heterogeneity in benefits: the range of welfare improvement is 1 to 15 percent, as opposed to uniform gains with perfect mobility.