高铁开通对县级单元产业结构的影响——以长三角地区为例

The Impact of High-speed Railway on the Industrial Structure of County-level Units:Taking the Yangtze River Delta as an Example

运用多期双重差分模型估计高铁开通对长三角地区县级单元产业结构的影响,并借助门槛效应和中介模型检验高铁效应的作用机制。结果显示:(1)高铁开通显著促进了县级单元的产业结构升级,非同步地推动第二产业的分散和第三产业的聚集。(2)人口规模对高铁效应存在部分中介作用,但在长三角县级单元中未发生门槛突变。(3)高铁开通对第三产业和第二产业的影响呈现不同的时间滞后性,致使县级单元产业结构转型存在两个窗口期,分别为开通当年和第3年。因此县级单元应立足自身情况并顺应高铁开通后的产业演化规律,以制定针对性的政策来激励或对冲。

Along with the rapid construction and extent of the high-speed railway network, almost all prefecture-level cities have enjoyed high-speed railway services, especially in the southeast coastal region. Therefore,the main body of high-speed railway construction has been transferred from connecting prefecture-level units to county-level units. However, current studies have rarely paid attention to the impact of the high-speed railway on county-level units. The purpose of this article is to explore what changes will take place in the industrial structure of county-level units after the opening of the high-speed railway and its mechanism. Taking the Yangtze River Delta as an example, it was evident that the sequence of high-speed rail opening and the evolution process of industrial structure in this region have significant synchronization. With the usage of socio-economic panel data of all county-level units in this region from 2000 to 2017, this article measured the impact of high-speed railways on the industrial structure through the time-varying difference-in-differences model and employed sub-grouping, threshold effect and mediation model to explore the mechanism of high-speed rail effect. The results of the study are listed as follows: 1) The opening of the high-speed railway will promote upgrading the industrial structure of county-level units, which is composed of the dispersion of the secondary industry and the aggregation of the tertiary industry. 2) Population size has partial mediating effect on the highspeed rail effect, but there is no threshold mutation within the population size range of the counties and countylevel cities in the Yangtze River Delta. 3) The secondary and tertiary industries have different time-laggings in the effect of the opening of the high-speed railway, resulting in two window periods for the transformation of the county-level unit industrial structure. When the county-level units apply for the high-speed railway project,it is necessary to judge their industrial characteristics prudently. And they should follow the law of industrial evolution after opening the high-speed rail and formulate targeted policies to encourage or hedge.