The first type is a radial national highway with Beijing as the center, numbered 1xx, such as the trunk highway from Beijing to Shenyang, numbered10/. There are 3 national highways 12, including 3 in the northeast, 2 in the north, 2 in the east 1, 2 in the south-central and northwest 1. 1 12 line is a circular line with Beijing as the center. At present, such national highways are mainly Class III and Class IV highways.
The second category is the north-south national highway (longitudinal national highway). Its number is 2xx, such as the trunk highway from Hegang to Dalian with the number of 20 1 national highway, the trunk highway from Shanhaiguan to Guangzhou with the number of 205 national highway, and the national highway with the number of 228 with the ring road of Taiwan Province Province. The longest national highway in the longitudinal direction is from Xilinhot to Hai 'an in the south of Leizhou Peninsula, with the number 207. This kind of national highway is mainly Grade III and IV.
The third category is the east-west national highway (transverse national highway), numbered 3xx. For example, the expressway from Suifenhe to Manzhouli is 30 1, and the expressway from Hangzhou to shenjiamen is 329. The route grades are mainly three and four. The longest horizontal national highway is the 3 17 national highway from Shanghai to Nyalam, which is also the longest national highway.