为了适应条件困难地形和受限制情况,将倒函数的概念、原理应用到立体交叉线形优化设计中,提出一种采用倒函数y=a/x作为立体交叉右转匝道线形的方法。通过分析该函数线形完全符合汽车行驶轨迹,并且与一般采用的缓和曲线-圆曲线-缓和曲线相比,能减小立体交叉的占地范围,同时缩短匝道长度,降低造价。文章分析了使用该函数线形为匝道时,采用圆曲线或缓和曲线设置匝道端部的方法。通过实例说明了倒函数设置立交右转匝道的具体求解方法。 In order to adapt to the conditions of difficult terrain and restricted conditions, the concept and principle of the inverse function are applied to the three-dimensional cross-line optimization design. A method of using the inverse function y = a / x as the right-turn ramp shape is proposed. The linearization of this function is completely consistent with the vehicle trajectory by analyzing this function, and compared with the general curve - curve - curve, it can reduce the scope of the crossing, reduce the ramp length and reduce the cost. The paper analyzes the method of setting the end of the ramp using a circular curve or a mild curve when using the linear function as a ramp. An example is given to show how to set up the right turn ramp for the inverse function.