Which highway is the S7 code for?

[Orville]

Highway S7 code refers to the Huchong Expressway. The Huchong Expressway, formerly known as A13 Highway, Chongming Cross-River West Line, and Riverside Expressway (Phase II). The S7 Expressway starts from the northwest section of Shanghai Outer Ring Expressway and ends at the Chongming section of Hushan Expressway, with a total length of approximately 28.7 kilometers. The principles for naming national expressways are as follows: 1. The naming of national expressway network routes should follow the general rules of highway naming. 2. The names of national expressway network routes are composed by adding a hyphen "－" between the starting and ending place names in the order of the route's start and end points. The abbreviated name of the route is represented by the first Chinese character of the starting and ending place names, or by the abbreviation of the province (city) where the starting and ending points are located. 3. The names and abbreviations of national expressway network routes cannot be repeated. 4. When two or more sections have the same starting and ending points, they are arranged in order from east to west or north to south.