Transit Service, Physical Agglomeration and Productivity in US Metropolitan Areas
研究了美国大都市区公共交通服务如何通过提高就业密度和人口密度，间接提升工资和人均生产总值，发现当前效益成本评估可能低估了公交改善的收益。
Public transit improvements could cause more clustered and higher-density employment and enable urban growth, giving rise to agglomeration economies by improving labour market accessibility, increasing information exchange and facilitating industrial specialisation. Using data on US metropolitan areas, this paper traces the links from transit service to central city employment density, urbanised area employment density and population; and from these physical agglomeration measures to average wages and per capita GMP. Significant indirect productivity effects of transit service are found. For example, in the case of central city employment density, estimated wage increases range between $1.5 million and $1.8 billion per metropolitan area yearly for a 10 per cent increase in transit seats or rail service miles per capita. Firms and households likely receive unanticipated agglomeration benefits from transit-induced densification and growth, and current benefit–cost evaluations may therefore underestimate the benefits of improving transit service, particularly in large cities with existing transit networks.