Collab:Bai Empire/National Roads

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The following is the documentation of the road network in the Bai Empire. Courtesy of kengoman and partly edited by zhenkang.


Please read this before reading through the documentation!

  • The proposed scheme only allows up to 27 major expressways, 72 minor expressways, and 999 national roads. While this doesn’t seem like a lot, keep in mind that most much larger countries don’t even have this high amount of expressways. If we were to max out the expressway numbering, especially with our current size, that means we have way, way too many routes.
  • All expressways are to be grade-separated with free flowing traffic. Keep this in mind.
  • National roads and provincial roads are not limited in its grade separation, free flow traffic, and speed limit, so it is absolutely possible and encouraged that some major ones can be mapped like expressways. Just make sure they have no tolls.
  • Please try to be as realistic as possible. The Emperor doesn’t have that much wealth as to warrant huge tunnels under Xiongjing for expressways.
  • Expressways should curve as infrequently as possible within budgetary limits. While we don’t want 100km tunnels under mountains, we also don’t want what is basically a tolled mountain road.
  • Specific numbering for national roads and expressways should be discussed on a case-by-case basis for major routes (高 1-高 9, 高#5, 高#0, all 环, and 国 1-99 routes). The rest can be numbered freely, with eastern/northern routes having a lower value than western/southern routes.
  • Numbers that are clearly troll or are unlucky in Chinese should be avoided or at least be discussed ie. 444, 666, etc.
  • Each provincial entity is allowed 99 expressway routes and 999 provincial roads. As will be discussed below, two digit provincial roads are major routes and if tolled become expressways. Three digit provincial roads are minor routes. Like national road numbering, maxing out the numbering probably means there are way too many routes.
  • Naming for national roads and provincial roads does not have to be consistent over the entire route. For major routes (like 国 1-99) the naming in any portion should be discussed.

National and Regional Expressways

Map Tagging: highway=motorway

These expressways must be 100% grade separated and free flowing with no less than 2 lanes per direction. Designated speed shall be no less than 80km/h (60km/h under special circumstances), with most being 100/120km/h. Furthermore, all expressways are tolled for both national and regional motorways. The reasoning for this is to reduce traffic demand on the motorways, with alternatives such as national and local roads running parallel to the motorways. Additionally and obviously, it is to generating income for maintaining the motorways and reducing the burden on motor taxes. Toll booths must exist at all interchanges (see below). ETC will be present on all tolled roads, so only off ramps need manned toll booths. Must be mapped as two separate one-ways.


National Expressways (百国高速)

For expressways funded 100% by the nation. Maintenance is at least 50% funded from the national government but works are conducted by the local authorities of the provinces it runs in.

  • ref=
    • Expressway code starts with “高” + at most two digits number (for main motorways); cannot start with “0”
    • 高 1 – 高 9 are routes of most importance
    • For major routes, "0 endings" (ie. 高 10, 高 20, 高 30…) are roughly North–South; "5 endings" (ie. 高 15, 高 25, 高 35…) are roughly East–West.
    • For minor routes, even endings for North-South (ie. 高 18, 高 46), odd endings for East-West (ie. 高 23, 高 57)
  • name=
    • [one character start location] + [one character end location] + [one character secondary end location] (optional) + “高速” (ie. for a route from Xiongjing to Riqing, “京庆高速”)
    • If following major geographical location, the motorway can name after the location, but no more than 3 characters before “高速” (ie. for a route along the east coast, “东海岸高速”)
    • If there are parallel motorways with similar start and ending termini, use prefix “第一”, “第二”… before the name. (parallel motorways with similar start and ending termini are largely discouraged unless necessary)

Provincial Expressways ([Province name] 省高速)

These expressways are at least 50% funded and maintained at the provincial level. These cannot run outside of the province it is in. However, if one does, its code and name can change when transiting into another entity.

  • ref=
    • [one character provincial shorthand] + two digit number
    • Specific numbers determined at the provincial level
  • name=
    • Same as National Expressway naming scheme
    • In addition, the name can be related to local culture, history, or famous person as well

Local/Inner City Expressways ([locality name] 城市/都市高速)

For expressways that are funded or maintained at the local level (municipality/counties/prefectures), with less than 50% of the funding provided by either the nation or province. Usually consists of inner city elevated/tunnel expressways.

While the speed limit can be reduced (still at least 60km/h) with more tolerance with slopes and curves, they are to remain grade separated, free flowing, and tolled.

  • ref=
    • Anything as long as it does not start with “高”, “环”, “国”, the number “0”, or any provincial shorthands. Can be solely consisted of numbers. No more than 4 character spaces and must be Hanzi (Baizi) characters or numerals.
  • name=
    • Anything + ending. Ending cannot be “高速”. Suggest “快速路”, “高架路”, “隧道”, or “线”. Try to keep the name as short as possible.
  • Special: Circular routes around major metropolitan cities start with “环” + one digit for the metropolitan area and one digit in case of multiple rings. Must be either Provincial or National Expressway. If as local expressway, follow local naming convention instead. Does not need to be full ring to have this attribute. Naming is [Number (ie. “第 1”, “第 2”…)] (Optional) + [metropolitan area] + “环线高速” (e.g. for the first (most inner) expressway ring around Xiongjing, ref= “环 11”, name= “第一雄京环线高速”)

Junction and Interchange tagging

For all types of expressways, junction and interchanges need to be tagged. At the split node, tag highway=motorway_junction

  • An interchange is an entrance/exit from the expressway to another road or another different expressway with a different toll

collection system (in the case of local to national/provincial if they don’t use the same toll system). Toll booths exist at interchanges.

  • A junction is an entrance/exit from one expressway onto another expressway sharing the same toll system. (i.e. there isn't a need for toll booths)
  • For ref= at both interchanges and junctions, the interchange number will be the distance (in kilometres) from the start for national expressways. For other expressways, linear numbers or kilometre numbers can be used.
    • When there are more than one interchange or junction within 500m (or when it makes sense), they will count as the same ref= number
  • For naming,
    • Interchanges are named [name] + “出入口” (in case it’s exit only or entrance only, only use either “出口” or “入口”).
    • Junctions are named [name] + “立交”
    • Name are to be kept as short as possible (preferably less than 4 character spaces)
  • The start and end of the expressway count as an interchange

National Roads (国道)

Map Tagging: highway=trunk The Bai National Roads must be 100% free to use. There are no strict requirements on their design speed, minimum lanes, grade separation, or free flowing traffic but will at least need to be paved. These roads are at least 50% funded at the national level. They are not necessarily constructed at national level, and any existing road can be designated as part of a national road. These roads also encompass the most important routes in the nation outside expressways, so there can be grade separation and free flowing traffic, provided they are free to use (without tolls). Medians usually exist for larger national roads and shall be mapped as two separate one-ways.


  • ref= “国” + number, number cannot start with 0 and at most 3 digits long
    • 国 1–国 25 are the most important routes in the nation and are longer, wider and more well-maintained
    • 国 26–国 99 are the slightly less important routes
    • 国 100+ are for other more minor routes

There is no strict guideline on the numbering of the trunk roads. Outside of 国 1 to 国 99, the numbering can be based on construction/repurpose timing.


Name can be anything from city roads to rural bypasses. They cannot adopt the “高速”, “快速路” or other endings that indicates in any way that this may be an expressway.

  • If the road isn’t named (which can be the case for most of the rural portions), it shall be named “国道” + [number] + “号”
  • Naming can be sectional and does not have to be consistent for the entire route. (ie. [name] + “路” in a city then back to “国道” + [number] + “号” once outside)
  • Suggested suffixes
    • 道、大道、公路 (roads)
    • 绕城线 (bypasses)
    • [start location] + [end location] + 线 (A-B line)

If the road is grade separated and free flowing, interchanges and junctions should be tagged as if it's an expressway, although without ref=

Provincial Roads (省道)

For roads that are at least 50% funded at the provincial level for its maintenance. These roads do not have to be originally built by the provincial authorities; they could have been repurposed from disused national roads as well.

  • highway=primary for major two or three digit numbered provincial roads that are not expressways (could use same number as expressway as non-tolled portion)
  • highway=secondary for minor three digit numbered provincial roads
  • Number scheme up to the province, ref= [one character provincial shorthand] + [number]
  • Naming scheme same as national roads
  • If not named, full province name + “省道” + number + “号”
  • Example: Qiongzhu Provincial Road 218, ref= 琼218, name = 琼珠省道218号

Local Roads

Extremely important major local roads can be highway=secondary, otherwise highway=tertiary

  • Include roads that are funded through an entity that’s not the nation or provincial level, or are private
  • No ref= allowed
  • Name can be anything as long as it is not implied to be an expressway and is suitable for its length (ie. no naming as “alley” for major road)
  • Must at least have one lane per direction or two lanes if one way. May map as two separate one-ways if a median exist.

Others (highway=unclassified, highway=residential)

  • Does not have to be named. Residential in residential areas, unclassified elsewhere. These are smaller streets, smaller than tertiary, usually without even a center line and shall be treated as such.

Other notes

  • Municipal expressways should exist in many major cities and some of them should have a different fare system. This is to make sure the mapping stays interesting over a broad range of localities.
  • Junctions and Interchanges for expressways:
    • Interchanges will mostly be double trumpet in rural areas. Urban area interchanges will be interesting to make as we want to save on land.
    • Try not to make 3-way junctions trumpets as they have a much lower capacity than other types.
    • Avoid cloverleaf as much as possible as there will almost always be a better solution. Certain very old portions may have a cloverleaf as a relic of the past
    • Partial Clover and any kinds of diamond interchanges are probably unrealistic as you will need toll booths for each ramp unless the situation calls for this layout.
    • Make sure the toll booths have enough room for cars to line up
  • Spaces between parallel roads:
    • Minimum 8m for two-lane parallel roads. 15m for 3-lane, 20m for 4-lane.
    • Minimum 10m for parallel expressways. (For reference: 20m for a 3 lane dual carriageway with decent shoulders and a good median, and 40m for 6 lanes)

Summary table

Country highway=
motorway trunk primary secondary tertiary unclassified residential
Bai flag.png Bai Empire National Expressways (百国高速), Provincial Expressways (省高速) and Local/Inner City Expressways (城市/都市高速). These expressways are 100% grade separated and free-flowing with no less than 2 lanes per direction. Designated speed shall be no less than 80km/h (60km/h under special circumstances), with most being 100/120km/h. Furthermore, all expressways are tolled for both national and regional motorways. National Roads (国道). Suffix “国” followed by a number. Toll-free. There are no strict requirements on their design speed, minimum lanes, grade separation, or free-flowing traffic but will at least need to be paved. Medians usually exist for larger national roads and shall be mapped as two separate one-ways. Provincial Roads (省道). Major roads serving within provinces. Usually with two-digits in ref tag. Provincial Roads (省道). Minor roads serving within provinces. Usually with three-digits in ref tag. Local roads without official ref tags. Not for use. Streets in residential areas.

Possible road suffixes

Baiyu name Ingerish name
高速公路 Expressway
高架路 Elevated Road
公路 Highway
环路 Ring Road
支路 Side Road / Branch Road
道/大道 Avenue
街/大街 Street
胡同 Hutong
支弄 Branch Alley

See also