I have long hoped to promote the use of highway=motorway for marking urban expressways in China for the following reasons:
In the road traffic safety law (implementation regulations), road-related national standards such as traffic signs (GB 5768.2), and GIS-related national standards such as GB/T 28443 “navigation electronic map graphic symbols” will be highways and urban expressways as equivalent roads.
Because of the urban expressway and national highway in osm are using trunk for marking, so that visually cause road function confusion, and there is a single prefecture-level city planning and construction of urban expressway can be well distinguished from other urban roads. The existence of part of the highway network sections actually urban expressway, some areas confusing highway planning caused by the highway sections difficult to include in the highway network.
Because China’s road system duality (the formation of “urban roads” and “highway” system), not through the planning of the administrative division of grade, and some developed prefecture-level cities are trying to mix the highway and expressway planning into “High expressway network”.
Try to Shanghai as a pilot city because:
Shanghai has a more complete urban expressway system throughout China
Shanghai, as a municipality directly under the central government, is a typical representative of a unified planning “high expressway network”.
Shanghai’s urban expressways are more standardized in the use of road signs (for national standards, ministry industry standards)
Several Shanghai expressways have been actually (e.g. S1, S5) or designated (e.g. S20) to take on the function of urban expressways
There is no number of such roads in Shanghai: Donghai Bridge
I hope this will explore some perfect prefecture-level city expressway network as motorway
"存在部分高速公路网路段实际为城市快速路、部分地区混乱的高速公路规划造成高速公路路段难以纳入高速公路网的范畴’ mean Describe two phenomena, one phenomenon is that the expressway is taking on the function of urban expressway; the other phenomenon is that the expressway network planned by the provincial government is very chaotic, and some expressway sections used illegal number or cannot be assigned Considered part of the locally planned highway network
If these urban expressways you mention are not built to motorway standards (such as having short-radius exits, lack of shoulders) or have other disqualifying features (like some at-grade intersections or some access to abutting properties), then the better tagging would be to use a highway=* tag appropriate to their connectivity importance and add expressway=yes to indicate the enhanced “expressway” construction:
highway=trunk for most important regional connections between cities
highway=primary for most important roads within an city that aren’t the main connections to other cities
highway=secondary for less important roads within a city.
Any of the road highway=trunk|primary|secondary|tertiary values can be paired with expressway=yes to indicate this enhanced construction. While the OSMCarto rendering on openstreetmap.org doesn’t differentiate roads tagged with expressway=yes yet, other renderers do. See this example of Austin, Texas, USA in the Americana renderer which highlights roads tagged expressway=yes versus the same view in OSMCarto.
It is reasonable that China’s expressways do not have road shoulders, because there are indeed some road sections carried by expressway routes without road shoulders. The main reason is that China, like some East Asian countries, has the phenomenon of separation of urban road systems and highways. The two systems have the highest level road types are legally equal
Based on my memory all the Shanghai expressway qualifies to be a highway=motorway. But please double check the area at Hongqiao Airport (T2) and Railway station. Those sections dropping off passengers are for sure no highway=motorway. Like Way: 185031852 | OpenStreetMap
You may want to change that back.