高速公路平纵曲线组合路段交通风险评估方法

A Method for Assessing the Risks of Freeway Segments with Combined Horizontal and Vertical Curves

高速公路平纵曲线组合路段常出现单一平曲线和竖曲线要素满足规范,但二者相结合后存在安全隐患的情况。为评估这类组合路段的交通风险、提升组合路段安全性,综合运用可拓云理论与理想点法,提出了基于可拓云模型的交通风险评估方法。基于已有事故数据和文献,从驾驶员、道路、交通环境以及其他因素的角度出发,构建了包含15个指标的交通风险评估指标体系,并将每个指标划分为5个风险等级;利用层次分析法和熵权法确定各评估指标主、客观权重后,再通过理想点法确定各评估指标组合权重;参照公路路线设计规范及相关文献,考虑定性指标的边界模糊性划分各评估指标的风险等级,并按照等比原则实现定性指标的定量化描述;构造可拓云模型云隶属度矩阵,计算综合评判向量,最后根据最大隶属度原则确定路段风险等级。以云南省3段高速公路路段作为分析案例,利用基于可拓云模型的交通风险评估方法计算了各路段风险等级,并识别了各路段的危险性指标。结果表明:该方法与传统基于模糊综合评价法相比,评估结果相同,但信息更丰富,其综合评判模糊等级特征值的期望E_(xr)反映了路段的安全程度;Y路段的E_(xr)高于C路段,表明Y路段比C路段更安全;3段路段的评估结果的置信度因子θ均小于0.05,表明结果可信度较高,验证了该方法在交通风险评估过程中的适用性。

Freeway segments with combined horizontal and vertical curves might not satisfy the safety specifica-tions of Highway Alignment Design(hereafter referred as HAD)even though each of them does so.To assess the risks of such road sections and improve road safety,a safety assessment method is proposed by using the extendable cloud theory and the ideal point method(IPM).Firstly,a road safety evaluation system is developed,which in-cludes 15 indicators from the following five perspectives:drivers,roads,traffic,environment,and others,and each indicator is coded as one of five levels.Secondly,subjective and objective weights of the indicators are determined by the analytic hierarchy process(AHP)and entropy weight method(EWM),respectively,which are combined in-to one using the ideal point method.Thirdly,the risk levels of each indicator are classified based on the specifica-tions,considering the fuzz boundaries of the qualitative indicators,and the qualitative indicators are quantified based on the principle of equal ratio.Finally,the membership evaluation matrix is developed,a comprehensive as-sessment vector is calculated,and the level of risk of road section is determined by the maximum membership prin-ciple.To demonstrate the proposed method,three cases from the Yunnan Province are used,and the results show that the proposed method not only provides compliant outcomes with the traditional fuzzy comprehensive assess-ment method but also offers more information.Specifically,the expected value of fuzzy grade eigenvalue for com-prehensive assessment,i.e.E_(xr),reflects the safety level of the road sections;Confidence Factorθreveals the reli-ability level of the result.In the studied cases,E_(xr)of Section Y is higher than that of Section C,showing that Sec-tion Y is safer than Section C;Confidence Factorθare all under 0.05,showing that the results are reliable.These results reveal the potential of the proposed method for road safety assessment.