This paper introduces a clear distinction between interregional and intraregional transportation cost in a mixed New Economic Geography and Urban Economics model (Krugman and Livas Elizondo 1996; Martin and Rogers 1995). With the assumptions that public spending on transport infrastructure has some different effects on city size and welfare, and that it is financed by a proportional tax on regional income, an absence of regulation enables productive activities to agglomerate in the most favored region. Considering the presence of urban costs (e.g. commuting costs and land rents), public transport policy for developed countries can be used as a strategic instrument for regional planning, leading to a decrease in the spatial size of cities.

中文翻译：

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公共交通政策对城市规模和福利的影响

本文在混合的《新经济地理学》和《城市经济学》模型中引入了区域间和区域内运输成本之间的明显区别（Krugman and Livas Elizondo 1996； Martin and Rogers 1995）。假设交通基础设施的公共支出会对城市规模和福利产生一些不同的影响，并由对地区收入征收一定比例的税收来提供资金，那么缺乏监管可以使生产活动在最惠国地区聚集。考虑到城市成本（例如通勤成本和土地租金）的存在，发达国家的公共交通政策可以用作区域规划的战略工具，从而减少城市的空间规模。