highway network levels的意思|示意

The highway traffic network construction in China is a developing trend. The highway systems at all levels in a region constitute the relatively closed network systems.

公路路网化是我国交通建设的一个发展趋势，各种不同等级的公路系统在一个区域内构成了一个相对封闭的路网系统。

Then divides the highway network into four levels: main trunk line, sub-trunk, feeder and connecting line, and also positions functions of the four levels.

进而按照通达程度将公路网划分为四个等级：主干线、次主干线、支线和连接线，并分别对四个层级进行了功能定位；