目前国外公路采用的曲线形式,主要是回旋曲线与圆曲线的各种不同形式的组合。比如,圆与直线之间采用回旋曲线连接过渡,是我们熟知的基本型式。其它形式的组合,如凸型曲线(用于克服极困难地段)和 At present, the curve forms adopted by foreign highways are mainly various combinations of the convolution curves and the circular curves. For example, the connection between a circle and a straight line using a clothoid transition is a well-known basic pattern. Other forms of combinations, such as convex curves (to overcome extremely difficult sections) and