Siyuan Bridge (simplified Chinese: 四元桥; traditional Chinese: 四元橋; pinyin: Sìyuán Qiáo) is a large, complex overpass in northeastern Beijing, China.Similar to Wuyuan Bridge further north and Sanyuan Bridge further south, it links three roads instead of just two for a normal overpass. The Airport Expressway, China National Highway 101, and the 4th Ring Road are linked.