公路重载运输的社会经济评估模型

为研究公路货运车辆重载运输对社会经济的影响,基于系统动力学理论建立了公路货运系统的仿真模型,通过仿真分析车辆载重程度对货运需求、车辆使用决策、车型演化、车辆运输成本以及路面性能的长期动态作用,继而进行公路重载运输的社会经济影响评估。基于安徽数据的仿真结果表明,在货运车辆普遍重载的条件下,生产要素价格的变动、路面厚度的提高和路面维修间隔期的改变均不会对车流轴载水平乃至公路货运系统的运行产生根本性影响,系统表现出较高的稳定性。此时,车辆载重标准的引入是极为必要的。在实施严格的车辆载重标准后,系统行为又表现出以下重要特征:反直观性、远期与近期利益相矛盾、系统绩效受产业结构的影响较大。

A Social-economic Evaluating Model for Highway Heavy-load Transport

In order to make evaluation on social-economic impacts of highway heavy-load transport,a methodological framework with a integrated system dynamics(SD) model,which include freight demand,vehicle usage,vehicle operating cost,vehicle evolvement and road performance sub-models,was established to simulate the transportation system quantificationally.As an application in Anhui,the long-term performance of highway heavy-load transport under different vehicle weight limit strategies were analyzed using above SD model.The sensitivity analysis results show that the highway freight system has poor sensitivity to fuel price,pavement thickness,pavement maintain interval and road user tax with the situation of ubiquitous overloading.Therefore,a set of moderate Vehicle Weight Limits are necessary to be introduced.The evaluation results show that under the rigid enforcement,the transportation system shows the following characteristics:not intuitionist to reveal,conflict between short-time benefit and long-date benefit,and the system performances are sensitive to area industry structure.