补贴政策对集装箱公铁联运竞争力的影响分析

Impact of Subsidy Policy on the Competitiveness of Container Rail-road Intermodal Transport

公铁联运因其具有运量大、成本低、环境友好等优势,世界各国采取一系列促进其发展的政策措施,补贴政策是其中一种有效且被广泛采用的政策.本文以补贴政策下政府部门、铁路公司和托运人之间相互作用机理为基础,构建了双层规划模型,上层模型描述了铁路公司制定集装箱班列开行方案的行为,下层模型描述了托运人在政府部门补贴下的选择行为.考虑到公铁联运网络中铁路弧具有"周期连接"和"速度异步改变机制"两种特性,本文分别通过网络拓展和定义分段阻抗函数来处理这两种特性.基于本文双层规划模型的结构,提出了混合遗传算法,即采用遗传算法求解班列的开行方案,使用连续平均算法求解下层的SUE模型.研究结论表明:在本文算例中,补贴额度增加的初始阶段(0.00～0.14元/(t?km)),补贴额度的增加对公铁联运竞争力的促进效果明显;但是超过0.14元/(t?km)后继续增加,对公铁联运竞争力的提升效果不明显.这种现象与既有研究有所不同,本文进一步分析了不同的原因.

A series of policies are put forward to promote the development of Rail-road Intermodal Transport(RRIT),because of its advantages of large transport capacity,low cost and environmental friendliness.We analyze the interaction mechanism between government,railway company and shippers under the subsidy policy,and then build a bi-level programming model.The upper model describes that the railway company decides the block train operational schemes,and the lower model represents shippers’choice behavior under government subsidies.Considering that the railway arc has the characteristics of“Periodic Connectivity”and“Asynchronous Change of Travel Speed”in the RRIT physical network,we represent these characteristics by means of network expansion and the segmented impedance function.Based on the structure of the bi-level programming model in this paper,a hybrid genetic algorithm is proposed to solve this model.The genetic algorithm is used to solve the upper model,and the method of successive averages is used to solve the SUE model in the lower model.The research conclusions show that the increase of the subsidy have a significant effect on promoting the competitiveness of RRIT in the first phase(0.00-0.14RMB/(t?km)),while the effect is little when the subsidy exceeds0.14RMB/(t·km).This conclusions is different from the existing research,and we further explain the reasons why they are different.