Abstract: To solve the problem of profit conflict between freight owners and highway operator which was caused by overload trucking,a system dynamics model was established for policy evaluation.By simulating interactions and feedbacks among transport issues such as freight volume,pavement damage,highway transport capacity and transport time under different policy scenarios,mechanism of profit conflict was analyzed and effective policy was given.Simulation for the case of iron ore transportation system from Caofeidian to Tangshan was conducted,and the results showed that limiting vehicle loads was not an effective policy because the increase of transport cost and time cost of freight owners caused by this policy was much higher than the decrease of pavement maintenance cost of highway operator.It was showed that vehicle loads limitation should be implemented on the basis of modal shift by railway.When railway reached class Ⅱ,cost decrease of freight owners and highway operator was higher than railway construction investment,which was effective for profit coordination within the system.

Key words: regional freight transportation system, system dynamics, vehicle overload control, policy, profit coordination

摘要： 为解决区域运输系统存在的货主超载运输导致的与公路运营方的利益冲突问题,建立了基于系统动力学的政策评价模型。该模型进一步考虑车辆严格限载和铁路介入等政策对货主时间成本的影响,通过模拟公路的货流量、路面磨损、运输能力和运输时间等环节间的互动与反馈,分析各主体利益的变化机理并给出有效策略,以协调各方利益。以曹妃甸至唐山的铁矿石运输系统为例进行仿真,结果表明：单纯的限载政策造成的货主运输成本和时间成本的增加大大高于公路运营方维护成本的降低,无法协调双方利益;通过建设铁路分流铁矿石,当铁路等级达到Ⅱ级时能同时降低双方成本,且双方累计节省的成本大于铁路建设投资,是公路严格限载下协调双方利益的有效政策。

关键词: 区域运输系统, 系统动力学, 超载治理, 政策, 利益协调