交通基础设施是影响经济增长的一个重要因素。交通基础设施具有典型的外部性，对交通基础设施进行投资，是调控经济、促进经济增长的重要方式。研究交通基础设施建设，对中国经济发展有很强的现实意义。无论是1998年亚洲金融危机，还是2008年全球经济危机，亦或是2020年全球新冠肺炎疫情，增加交通基础设施投资都是中国政府刺激经济的一项重要措施。

交通基础设施不仅可以直接创造需求，促进经济增长，而且具有网络效应，能间接对经济产生长期影响。本文利用2002年至2019年中国省级面板数据，探究交通基础设施对经济增长的影响机制。首先，通过生产函数模型探究交通基础设施对经济增长的贡献率，并探讨交通基础设施与市场化进程对经济增长的协同合作效应；其次，采用中介效应模型探究交通基础设施影响经济增长的途径；最后，采用空间面板数据模型进一步研究交通基础设施的空间溢出效应。

研究结果表明：交通基础设施对中国经济增长具有显著的正向作用，在2002年至2019年间，交通基础设施对中国经济增长的贡献率达到11.755%，并具有显著的时间阶段分异特征。加入市场化指标及交通基础设施和市场化交互项指标后，发现两者的交互项系数显著为负数，说明随着市场化进程不断推进，中国交通基础设施对经济增长的影响逐渐减弱。中介效应模型表明，交通基础设施的确可以通过影响经济要素流动，进而影响经济增长，即经济要素流动是交通基础设施影响中国经济增长的一个重要途径。若交通基础设施增加1个单位，就能通过经济要素流动带来经济增长增加1.870%。空间面板数据模型进一步表明，中国交通基础设施对省域经济增长具有显著的正向作用，而且本地区的交通基础设施对临近地区的经济增长具有显著的促进作用，即具有正向空间外溢效应，并且这种空间溢出效应具有明显的地域和时段分异的特征。

本文研究结论凸显未来加强交通基础设施建设和深化市场化改革的重要意义，也为各省份根据本省省情实施差异化政策以促进经济增长提供依据。

Transportation infrastructure is an important factor affecting economic growth. Transportation infrastructure has typical economic externalities. Investment in transportation infrastructure is a significant way to regulate economy and promote economic growth. The study of transportation infrastructure is of great practical significance to China's economic development. Increasing investment in transportation infrastructure is an important measure for the Chinese government to stimulate the economy, whether it is the Asian financial crisis in 1998, the global economic crisis in 2008, or the global outbreak of COVID-19 pneumonia in 2020 .

Transportation infrastructure can not only create demand and promote economic growth directly, but also has network effect, which can have a long-term impact on the economy indirectly. This paper uses provincial panel data from 2002 to 2019 to explore the impact mechanism of transportation infrastructure on economic growth. Firstly, through the production function model, this paper explores the contribution rate of transportation infrastructure to economic growth, and discusses the collaborative effect of transportation infrastructure and market-oriented reform on economic growth. Secondly, the mediating effect model is used to explore the ways of transportation infrastructure affecting economic growth. Finally, the spatial panel data model is used to study the spatial spillover effect of transportation infrastructure.

The results show that transportation infrastructure has a significant positive effect on economic growth. From 2002 to 2019, the contribution rate of transportation infrastructure to economic growth reaches 11.755%, and there are differences in different time periods. After adding the marketization index and the interaction index of transportation infrastructure and marketization, it is found that the interaction coefficient is significantly negative. This shows that with the advancement of market-oriented reform, the impact of China's transportation infrastructure on economic growth is gradually weakening. If the transportation infrastructure is increased by 1 unit, the economic growth will increase by 1.870% through the flow of economic factors. The mediating effect model shows that transportation infrastructure can affect economic growth by influencing the flow of economic factors. That is to say, the flow of economic factors is an important way for transportation infrastructure to affect economic growth. The spatial panel data model further shows that China's transportation infrastructure has a significant positive effect on provincial economic growth. Moreover, the transportation infrastructure of the region has a significant role in promoting the economic growth of the adjacent areas, that is, it has a positive spatial spillover effect. Further more, the spatial spillover effect varies according to the region and time.

The conclusion of this paper highlights the importance of strengthening the construction of transportation infrastructure and deepening the market-oriented reform in the future. It also provides the basis for the provinces to implement differentiation policies to promote economic growth.