中国运输成本和效率对出口贸易影响的实证研究

Analysis on transport costs and China's exports

本文首次将贸易引力模型扩展并应用到中国港口城市交通运输成本和效率对我国出口贸易影响的研究中.并基于我国四大港口城市出口到32个国家和中国香港的1997-2008年面板数据进行了实证研究,主要研究结果可总结为3点:1)我国公路运输成本和港口效率是影响我国贸易扩展的主要因素.在控制了贸易引力模型中的其他相关变量,我国港口城市公路运输成本每增加10%,将减少出口贸易额大约9%;港口效率每提高10%,将给中国出口带来7.2%的增长;2)公路成本、铁路成本和港口效率代理变量的总弹性在中国出口亚洲子样本模型中弹性最大,这3个变量对中国出口欧洲和美洲的影响与总样本模型结果相似,弹性不同主要来自于港口效率指标在不同模型中的不同影响,表明我国港口效率的提高不仅有利于提高我国在全球出口份额,而且还对我国出口结构产生相应地影响;3)在控制了贸易引力模型中的其他相关变量,公路成本、铁路成本和港口效率代理变量的总弹性为1.66,几乎是平均工资弹性的3倍,表明有效地利用和提高我国不同运输模式的运作效率是保持和增强我国出口产品的竞争优势的有效手段.

Based on the annual data set,which involves a balanced panel of four port cities exports to 32 countries and Hong Kong,China over the period of 1997-2008,this paper is the first attempt to extend the conventional gravity model to measure the effect of transport costs and port efficiency on China＇s exports.Our results can be summarized in three main findings：1） the improvement of port efficiency and reduction of road transport costs play a vital role in China＇s export competitiveness in the global market. The coefficient estimates on them are relatively large,around 0.72 and-0.89,respectively;2） the effect of transport costs and port efficiency on China-to-Asia exports significantly exceeds that on China-to-Europe and China-to-America exports;3） the overall estimated elasticity of road,railroad and port measure is 1.66,which is almost three times that of the average wage of port cities.The empirical results provide strong evidences that improvement in the quality of transportation services in port cities of China exhibit significant economic effects not only on how much but also how trade grows.