Abstract: In order to maintain the stability of import supply chain, China needs to improve firms' status of import trade network. With the development of economic globalization, tariffs in various countries have been greatly reduced, and the role of tariff trade barriers has gradually been weakened. People are paying more and more attention to the impact of non-tariff costs such as transportation infrastructure on trade.
Can transportation network contribute to improving firms' status of import trade network? What exactly are the channels through which transportation network improves firms' status of import trade network? To make this question clear, this paper analyzes the link between transportation networks and firms' status of import trade network by reviewing available literature. Theoretically, transportation network may have an impact on firms' status of import trade network through both production-side inventory reduction and sales-side market expansion. For one thing, well-developed transportation network alleviates the pressure of inventory costs by facilitating information sharing between suppliers and clients and reducing the difficulty of supply chain coordination and access, which can improve firms' propensity of import and firms' status of import trade network. For another, transportation network can expand sales markets and profit margins by smashing market segmentation and facilitating cross-regional flow of factors, which is able to elevate the status of the import trade network. This paper then constructs a global trade network matrix among 196 countries in the world and calculates the PageRank of Chinese manufacturing firms,so as to measure firms' status of import trade networks. Next, this paper calculates the indicators of the overall market access and the disaggregated market access based on the information of cities, such as the opening of high-speed railways, highways and other common transportation infrastructure, and empirically analyzes the relationship between the market access and the PageRank of the import trade network. Finally, this paper conducts a more detailed discussion on the specific channels of the reduction of the inventory cost and the expansion of the sales market by distinguishing firm samples with different degrees of transportation dependence, internet development, and local protection, so as to verify whether the market access has a differential impact on the status of theimport trade network from different firms.
The results of the study are as follows: (1)Market access has significantly promoted the improvement of firms' status of import trade network. It is worth mentioning that market access due to high-speed railways and market access due to highways play a particularly important role in this study. After a series of endogeneity treatments and robustness tests such as changing the calculation method of explanatory variables, changing the time horizon of research samples, and taking the lagged term of the core explanatory variables into regression, these conclusions still hold true. (2)Market access, as an important indicator for measuring domestic transportation cost, can indeed enhance firms' status of import trade network by reducing inventory cost and expanding sales market. (3)It is subject to firm heterogeneity in terms of the performance of the market access in promoting the status of import trade network. Transportation-dependent firms need more developed transportation network, and these firms' status of import trade network are more sensitive to the increase in market access. The internet helps firms reduce information search costs. When market access increases, firms with a high degree of internet development can more fully utilize their online and offline comprehensive advantages to enhance their status of import trade network. In areas with a low degree of local protection, the increase in market access will expand firms' domestic sale, thereby enhancing their status of import trade network.
The findings of this paper have important policy implications. First, in order to improve the domestic grand circulation and the international grand circulation, government should continuously promote the further improvement of the infrastructure construction with the integration of sea, land and air transportation network. Transportation network can foster the cross-regional flow of domestic factors, and strive to reduce the non-tariff trade costs. Firms can expand their network of trading partners with cost advantages, and enhance their status of import trade network, thus reducing the over-dependence on the single import industry and market in the past. Furthermore, in order to give full play to the positive role of transportation on trade development, government should build a more effective internet information sharing platform for firms to form the “online” and “offline” intelligent interoperability model through the combination of the internet and transportation networks. In addition, government should provide a better economic environment for building a trader of quality by gradually eliminating local protection, and continuously evaluating the business environment.

Key words: Transportation Network, Market Access, The Status of Import Trade Network, PageRank

摘要： 本文通过构建市场接入度指标衡量综合性交通网络带来的境内贸易成本降低效应,使用2000—2013年中国制造业企业微观数据测算企业进口贸易网络的PageRank值,系统探究市场接入度对企业进口贸易网络地位的影响及其作用机制。研究结果表明,市场接入度显著提升企业进口贸易网络地位,其中高铁网络和高速公路网络引致的市场接入度发挥的作用尤为明显;在考虑内生性问题和稳健性检验后,该结论依然成立。从传导机制上看,库存成本下降和销售市场拓展是市场接入度提升企业进口贸易网络地位的重要途径,且对交通依赖度、互联网发展程度、地方保护程度不同的企业的影响具有异质性。

关键词: 交通网络, 市场接入度, 进口贸易网络地位, PageRank值