Because of the complex topography,the highway routes arecomposed of straight and Curved line segments on the plane as for buildinghighways in mountainous areas.According to the varied mountain area geogr-aphical features,transport capacity and the highway standard,we have toselect rational plane Curves and neighbouring curves etc.All of these are notonly for the artistic value of road appearance and raising the class of highw-ays,but also for Cutting down the cost of engineering,improving the vehicl...
