基于车辆限速的危险品运输网络优化研究

Transportation network optimization of the hazardous materials based on the vehicle speed limit

在危险品运输网络中,对不同路段上危险品运输车辆的最高车速设置不同的强行限制,能在很大程度上影响危险品运输商的路径选择,从而导致不同的危险品运输网络总风险和总成本。首先基于车辆限速的方法,构建了危险品运输网络优化的双层规划模型,上层规划以网络总风险和总时间成本的加权最小化为目标,下层规划以危险品运输企业的总时间成本最小化为目标;然后,采用粒子群优化算法求解该模型;最后,通过算例验证了模型和算法的有效性。结果表明,政府部门运用车辆限速方法,在兼顾企业利益的同时,能有效降低危险品运输网络的总风险。

The present paper is aimed to put forward a speed limit strategy for the hazardous materials(hazmat) vehicles in moving on the different category roads in hoping to minimize the total travel cost(TTC) and the total travel risk(TTR).To clarify the purpose of the topic,we have first of all analyzed the limitations and restrictions of the former road forbidding or heavy charging strategies for the sake of reducing the TTC and TTR of the hazmat transportation network as far as possible.Secondly,efforts have been made to clarify the close relation between the vehicular speed and the traffic accident,so as to make an analysis of the relation between the different limitation rules imposed on the maximum speed of hazmat vehicles on different links and the effects that have been brought about in the hazmat transportation network,which may greatly affect the route selection of the hazmat carriers and eventually result in the different TTC and TTR in the given hazmat transportation network.And,thirdly,the paper has established a bi-level programming model for the hazmat transportation network optimization proposal based on the approach of vehicle speed limitation mentioned above,in which the upper limit restrictions have been set up so as to minimize the weight sum of TTC and TTR,whereas the lower level initial provision intends to focus on minimizing the total transportation per-capital cost for such hazmat carriers.And,fourthly,a bi-level programming model we have initiated is inclined to realize the reasonable calculation of transportation economy through the particle swarm optimization algorithm.And,finally,we have given a numerical example to verify the effectiveness of the model and the algorithm.The results of our work show that,on the one hand,the optimized vehicle speed limit on each road link can vary with the corresponding official transportation rules set by the local governmental organs and,on the other,onto the TTR of the hazmat transport network.In so doing,the governmental offices can effectively reduce the TTC and TTR cost of the hazmat transport network in their own attitudes to the vehicle speed limits on the condition of sacrificing the profits to be gained from such hazmat carriers.