南京地铁对城市公共交通网络通达性的影响及地价增值响应

以南京地铁1、2 号线为例，通过多个指标测度地铁建成前后的交通通达性及其格局变化，探讨不同类型用地对地铁通达性的增值响应模式。研究结果表明：地铁从时间成本、影响范围等方面增益了研究区交通通达性；外围绝对通达性增幅高于中心区，而“半径陷阱”作用使得中心区的相对通达性高于外围，产生“中心膨胀-外围坍缩”的通达性格局变化；地价格局变化与通达性格局变化类似，不同类型用地对地铁的增值响应模式不同，商业用地增值为对数响应模式、住宅用地为指数响应模式、工业用地为线性响应模式；地铁对城市土地升值的贡献占到总量的1/3，其中地铁对商业用地外部性作用大于住宅和工业用地。研究结果可为评估地铁对城市土地利用影响、城市经济外部性以及制订征收差别化的土地房屋税收政策提供依据。

The impact of metro lines on public transit accessibility and land value capture in Nanjing

This paper takes Nanjing metro Line 1 and Line 2 as an example to construct the urban public transit network, which is used to measure the changes in transit accessibility with multiple indicators. Based on the distinctions between before and after building metro line, this paper provides diverse value added response modes with different land prices capture on the transit accessibility-added of metro, which offers a scientific basis for law inquiry and policy formulation. The results show that the metro enhances the urban public transit accessibility in time costs, sphere of influence, and network morphology and so on. Absolute accessibility increase in the peripheral region is larger than that in the central area, while relative accessibility increase in the center is larger because of "radius trap", which brings about "center expansion & peripheral collapse" pattern change. The change of land price pattern is similar with that of accessibility pattern. Thus, space differentiated external economy comes into being with the effects of metro. Different types of land use have different land value capture modes, for example, commercial land value increase shows a logarithmic response mode, residential land value increase shows an index response mode, while industrial land value increase shows a linear response mode. It is indicated that metro contributes 1/3 to urban land added value, in which the external effect on commercial land is higher than that of residential and industrial land, with a ratio of 2:1:0.3. The result may be beneficial to assess the Nanjing Metro influences on the overall urban land use, and provide the evidence for levying urban land and housing differentiated taxes to compensate the metro economic externality losses.