Productivity and wage effects of an exogenous improvement in transport infrastructure: Accessibility and the Great Belt Bridge
研究大贝尔特桥开通对丹麦企业生产率和工人工资的影响，发现可达性提升显著促进生产率和工资，但工资效应更局部；劳动力市场匹配的生产率效应大于可达性效应，但仅惠及少数企业；桥梁主要使高学历和男性工人受益，加剧了工资不平等。
In this paper, we study the productivity and wage effects of a large and very localized discrete shock in the quality of transport infrastructure, viz. the opening of the Great Belt Bridge connecting the Copenhagen area with the neighboring island Funen and the mainland of Denmark. We focus on two effects: (i) an accessibility externality, captured via changes in an accessibility indicator at the municipal level; (ii) better matching of workers to jobs, enabled by to the shorter travel times after the opening of the bridge. We can disentangle the accessibility and matching effects, because better matching is only realized via new commutes crossing the Great Belt after the opening of the bridge. Our results show that the increased accessibility had significant positive effects on productivity as well as wages, the latter being much more localized. The productivity effects of improved labour market matching are larger than the accessibility effects, but they are restricted to a small share of the firms. We find a modest wage effect of better matching, suggesting that employees get a small wage increase on top of the commuting cost savings associated with the opening of the bridge. Overall, the estimates suggest that firms benefited more from the opening of the bridge than did workers. Moreover, the bridge benefited mainly highly educated and male workers, and it increased wage inequality.