The China National Highways of Beijing article focuses on Beijing, as a national transport hub, is the starting point for eleven of the twelve series-100 China National Highways. These are major (some toll) truck routes, primarily intended to connect Beijing with the rest of China.
China National Highway 112, despite being a series-100 China National Highway, does not begin Beijing, but begins in Gaobeidian and forms a long ring route.
The 'G' in front of the highway route numbers stands for 国 (pinyin: guó), meaning nation or country.