The building of highways is seen as key to accelerating infrastructure construction. In 2003, completed investment in highway construction was 350 billion yuan and 219 key highway projects progressed, focusing mainly on the five north–south and seven east–west national arterial highways as well as highways in western China and in rural areas. By the end of 2004, the total length of highways open to traffic reached 1.871 million km, including 34,300 km (21,300 mi) of expressways up to advanced modern transportation standard, ranking second in the world. The nation's highway density has now reached 19.5 km per 100 km2.
With the completion in 2008 of the five north–south and the seven east–west national arterial highways, totaling 35,000 km (22,000 mi), Beijing and Shanghai were linked by major highways, chiefly expressways, to the capitals of all provinces and autonomous regions of China, creating highway connections between over 200 cities.
The aim of the National Expressway Network Plan approved in early 2005 is an expressway system connecting all capitals of provinces and autonomous regions with Beijing and with each other, linking major cities and important counties. The network will have a total length of about 85,000 km (53,000 mi), including seven originating in Beijing; the Beijing-Shanghai, Beijing-Taipei, Beijing-Hong Kong-Macau, Beijing-Kunming, Beijing-Lhasa, Beijing-Ürümqi, and Beijing-Harbin expressways. Half of the projects are already completed.
In 2013 the Ministry of Transport announced the "National Highway Network Planning (2013 - 2030)", which will bring the total number of highways to 119, with 81 connecting highways between them. The total mileage will be increased to 265,000 km (165,000 mi), with increased focus on the western and less developed regions.
Although an accepted speed limit on China National Highways is 120 km/h, it is common to see cars pass other by in excess of 120 km/h. The lack of speed detection cameras on some routes, lack of a posted speed limit outside of localities and tremendous distances of road mileage, means that enforcing this speed limit is rather herculean. In addition, there is a notable shortage of traffic police in mainland China.
Nationwide highways often begin with the letter GXXX, followed by three numerals, e.g.: G107. It is said that the GXXX stands for 国家 (guójiā), or national.
The numbering of the highways is as follows:
Five vertical and seven horizontal main routes were labelled in the former 000 series (the so-called "five downs and seven acrosses"), although these have been deprecated in favour of the "NTHS" (7, 11, 18) system.
5000 kilometer milestone on G318, the longest China National Highway, in Lhatse County, Tibet.
Road sign using the old GZXX format
Highways listed in red are under construction or still in planning. Those listed in yellow are currently partially finished. Those listed in grey were planned but never built, or have been abandoned or redesignated.
Note: 000 Series China National Highways pointed to five specific vertical routes, as well as seven specific horizontal routes. Routes ending in "0" were north–south (vertical) routes; routes ending in "5" were east–west (horizontal) routes. The new system with two to four numbers that indicate the "NTHS" (7918) system is now in use instead of the 000 Series. For the expressways' new numbering system, see Expressways of China.
It seems that the old 0xx numbers are still signposted[when?] using the format GZXX, e.g. in the Qinghai province, there are signs at the G109 (old G025) showing the number GZ25.
Taiwan outside PRC's control, but a recognition of the ring part of Taiwan's highway as of national importance. As of 2000s maps depict G228 as "Converted to Provicial Highways" (together with G226/G315 that were really converted to provincial highways). Designation abandoned in 2013 in favour of a ring around mainland instead(see below).
China National Highway 112 runs around Beijing
Before 2013, Mainland China observed National Highway 228 as Taiwan Ring, composed of several National Expressway (Republic of China) and Taiwan provincial highways, this designation is not recognized by Republic of China (Taiwan). This observation was eventually dropped in new National Highway plans, replaced by Dandong-Dongxing Highway.
A extension plan of the highway system was announced in 2013, including extension of existing highways(101-112, 201-227, 301-330) and new highways (North-South 228-248, East-West 331-361, Connections 501-581). Only small portions of them needs to be constructed from scratch; most of the new highways would be upgraded provincial/county highways.