山区高速公路的规划设计是通过合规性检查来保障其运营安全的。然而，仅仅依赖于合规性检查会误导工程设计人员在实际操作中选取符合规范的且成本造价最低的方案作为最终的设计方案，而该方案的整体风险水平却是未知的，这将给项目运营带来巨大的安全隐患。本文提出了一种基于成本- 安全均衡的高速公路规划设计方法，该方法主要包括以下四个步骤：① 分别提取项目成本与安全的影响因素，以少量参数化的方式来表达高速公路的设计方案；② 建立风险因素与项目成本之间的预估方程式；③ 通过构造事故树模型，在众多设计参数中识别出风险因素；④ 将可接受风险分析理论引入交通安全评价中，提出了一种在可接受风险范围内求解具有成本效益的最优解的算法，以帮助管理者决策。该方法在位于海拔梯度大、山脉范围广的川藏高速公路工程项目中得到了应用和验证。实验结果表明，该方法显著提高了项目设计的安全性以及成本效益。

Engineering designs for mountainous highways emphasize compliance checking to ensure safety. However, relying
solely on compliance checking may lead designers to minimize costs at the expense of high risk indicators, since the overall risk level of the highway design is unknown to the designers. This paper describes a method for the simultaneous consideration of traffic safety risks and the associated cost burden related to the appropriate planning and design of a mountainous highway. The method can be carried out in four steps: First, the highway design is represented by a new parametric framework to extract the key design variables that affect not only the life-cycle cost but also the operational safety. Second, the relationship between the life-cycle cost and the operational safety risk factors is established in the cost-estimation functions. Third, a fault tree analysis (FTA) is introduced to identify the traffic risk factors from the design variables. The safety performance of the design solutions is also assessed by the generalized linear-regression model. Fourth, a theory of acceptable risk analysis is introduced to the traffic safety assessment, and a computing algorithm is proposed to solve for a cost-efficient optimal solution within the range of acceptable risk, in order to help decision-makers. This approach was applied and examined in the Sichuan-Tibet Highway engineering project, which is located in a complex area with a large elevation gradient and a wide range of mountains. The experimental results show that the proposed approach significantly improved both the safety and cost performance of the project in the study area.