“轴—辐”式运输网络的范围经济问题

Economies of Scope of "Hub and Spoke" Transportation Network

为证明"轴—辐"式运输网络有独立于密度经济而存在的范围经济,在假设运输网络密度收益不变的前提下建立了独立分段运营与整合运营两种模式下运输网络的成本函数,对比发现,采用独立分段运营与"轴—辐"式整合运营两种模式的运输网络运营成本差异较大,当采用"轴—辐"式整合运营模式且运输网络达到最佳运营结构时才能实现范围经济,其原因在于采用"轴—辐"式整合运营模式进行运营线路整合优化时能使营运车辆及人员工作效率得到提高.结果表明,密度收益恒定时"轴—辐"式网络运营模式下存在范围经济,但范围经济的取得需通过运营线路结构优化才能实现.

To testify, that economics of scope is independent of economies of density in ＂hub and spoke＂ transportation network, two cost functions are formulated based on two kinds of route structures ： separate two nodes system and hub-spoke system with constant returns to density. The calculation of the transportation cost of the two kinds of route structures in the same transportation network reveals that different route structures have very different transportation cost. Only optimal route structures of ＂hub and spoke＂ transportation network could provide economics of scope for the expansion progress because of the acquisition of the highest vehicle and staff operational efficiency from aggregated flow of ＂hub and spoke＂ transportation network. The results indicate that economics of scope can be obtained in ＂hub and spoke＂ transportation network with optimal route structures when the ＂hub and spoke＂ transportation network has constant returns to density.