Highway Tag Africa
Typology of Road Network in African countries
From the experience with the Activations in various countries, the Humanitarian OpenStreetMap Team community has developed this classification of roads more adapted to the context of African countries. Before you make modifications to this page, you are invited to come and discuss on the HOT Discussion list
The road conditions in African countries do not always correspond to their economic and social role. A road typology should be based on the road importance and not on the surface or the visual appearance of a road. In some areas, major roads are unpaved and heavily damaged during the rainy season. It is important for remote mappers to adapt to this reality. In some areas, such as the Sahel, it is also important to consider the density of the road network.
This proposed typology for African countries is based on mapping experience in various countries, observations and discussions. In some areas, there is a very dense network of roads with many tracks going in all directions. In such a context, it is important to have a hierarchy of roads that highlights the more important ones for economic activities. highway=tertiary is used to highlight roads interconnecting with regional service towns. Also, highway=unclassified is used to distinguish rural roads interconnecting villages from tracks going to the outskirts of villages. If you're in doubt of what tag to use, use highway=road, keeping in mind that many highways are formed by repeated foot and animal traffic.
The individual mappers should classify a particular road when adding it in the OSM database. Once the network of road is completed, we have an overview of the road network, and experienced mappers can then revise this network and ensure that the hierarchy of major roads is clearly established.
This is open to suggestions, please share your experience/practices from other countries. To communicate, use the Hot mailing list.
The Highway tag reflects the Economic and social dimension of the road.
|highway||motorway||A restricted access major divided highway, normally with 2 or more running lanes plus emergency hard shoulder. Equivalent to the Freeway, Autobahn, etc..|
|highway||primary||The main axes connecting the big cities.|
|highway||secondary||The roads connecting with regional capital cities and the towns of some importance (health services, commerce, etc.).|
|highway||tertiary||The roads interconnecting villages and the major streets in towns of some importance.|
|highway||residential||Used for roads in the residential areas except the major streets that interconnect with various roads (ie. primary, secondary, tertiary).|
|highway||unclassified||The roads serving for interconnection of smaller villages and hamlets.|
|highway||track||The small roads going outside the residential areas, mainly for agricultural and forestry purposes. In general these roads do not have connecting function with other roads.|
|highway||path||Paths not large enough for cars and mainly for pedestrians, both inside and outside residential areas.|
Road surface status
One can indicate the physical surface of the road with the surface tag:
Generically, a hard surface (asphalt, cobblestone, concrete...) is indicated with surface=paved and a soft one (ground, sand...) with surface=unpaved.
By default, primary/secondary/tertiary/unclassified/residential and service highway=* are supposed to be paved. If it is not the case, one must mention it, especially if the surface is soft. When potholes represent more than 50% of the surface, the way may be considered as unpaved.
In addition to surface material, on can indicate "viability" or "roughness" of the road with smoothness=*. This should help determining which kind of vehicle may use the road or the track.
|good||Usable with racing bike|
|intermediate||Usable with city bike, sport cars, scooter...|
|bad||Usable with trekking bike, "normal" cars. One can not exclude potholes.|
|very_bad||Usable with car with high clearance. Typically with 404 bachée. "Normal" cars can't go through.|
|horrible||4Wheel drive only.|
|very_horrible||4Wheel drive cars can't go through or it is very difficult, with help of winch. Usable with tractor, ATV, motorcycle, zebu carts.|
|impassable||No wheeled vehicle. Road damaged for instance.|
A suggestion would be to smoothness only when it is equal or lower than bad.
An approximative closing period can be provided with a conditional restriction :
access:conditional=no @ Dec-Apr: this track is usually closed from December to April (or open from May to November).
For the more complicated case where a track may be usable by 4Wheel drive car during dry season but only with zebu carts in rainy season, the following scheme is suitable:
When a road is crossing a river, whatever it is with a bridge, an organized ford ("radier", "baden") or natural ford, it should be tagged on the portion of the road affected. If the crossing section is too small (or difficult to separate the two ends), we put the information only on one point.
Some bridges have (wood) beams oriented in the drive direction so that there is only two narrow ways for the wheels. It is a problem for bicycles and motorcycles that can not cross such bridges:
surface=wood:lanes if beams are made of wood If bicycles and motorcycles can cross the river near the bridge, for instance by going in the river and using a ford, you should add the alternative track.
For river crossing with natural or organized ford, one should use flood_prone=yes. depth=* allows to indicate the usual (dry season, out of flood or hurricane) depth of the water. depth=0 will be used for crossing usually dry but that may be used upon water. In opposite, a crossing usually dry that become dangerous to use once water is flooding will be tagged as flood_prone=yes. surface=* will be used to indicated if the crossing is organized. Typically surface=concrete for an organized ford made of concrete.
Some bridges may be submerged, i.e. water may run other the bridge during flood. If one can still use the bridge with some water over it, this can be considered as a combination of bridge and dry ford : bridge=yes, ford=yes and depth=0. If one can not use the bridge with water over it, use bridge=yes and flood_prone=yes. They are usually made of concrete : surface=concrete.
In some areas, there are no formal paths, but several unpaved paths [example] very close to each other (within 100m) that all lead to the same destination or town. As of now, practice has been to add a way to the centermost or average of these paths. previous discussion]