公路线形设计作为公路建设的重要环节，其设计质量的好坏直接影响到行车安全和舒适． 为了改善现行平、纵分离式路线设计方法存在的不足，文中从公路中心线是一
条空间曲线的本质出发，采用曲率和挠率作为设计参数，建立了一种新的公路三维线形设计方法． 在此基础上，分别从几何连续性、车辆稳定性和行车舒适性3 个方面对公路三维线形应满足的工程约束条件进行了研究分析，并建立了相应的约束模型． 在借鉴现有设计规范和经验的基础上，结合已建立的约束模型，最终确定了不同设计速度下三维线形指标应满足的设计约束值． 新的线形设计方法可以避免传统方法中平、纵线形组合无法量化分析，以及组合线形空间连续性衰减等问题，为提高公路线形设计的安全性提供了新的思路．

Highway geometric design is an important part of highway construction,which directly influences the safety and comfort of driving.In order to overcome the shortcomings of the separated horizontal and vertical alignment design methods,by adopting the curvature and the torsion as new alignment design indexes,a new method for the three-dimensional highway geometric design is developed based on the fact that the highway centerline is a three-dimensional curve in nature.Then,by analyzing the engineering constrains of the three-dimensional highway alignment design from the aspects of geometric continuity,vehicle stability and driving comfort,a constraint model is constructed.Finally,the design values of the three-dimensional alignment indexes at different design speeds are determined based on the current design guidelines and experiences and by integrating the constructed constraint model.This new design method can avoid the limitations of unmeasurable combined effects and geometric continuity degradation in the traditional design method,and it provides a new solution to improving the safety of highway alignment design.