Highway Tag Africa

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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

Goal

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.

Proposed tags

Economic and social dimension of the road

The Highway tag reflects the Economic and social dimension of the road.

Key Value Element Comment Rendering Photo
Roads
highway motorway Way A restricted access major divided highway, normally with 2 or more running lanes plus emergency hard shoulder. Equivalent to the Freeway, Autobahn, etc..
Rendering-highway motorway neutral.png
Motorway-photo.jpg
highway primary Way The main axes connecting the big cities. Rendering-highway primary neutral.png
Ea highway primary.JPG
highway secondary Way The roads connecting with regional capital cities and the towns of some importance (health services, commerce, etc.). Rendering-highway secondary neutral.png Ea highway secondary.JPG
highway tertiary Way The roads interconnecting villages and the major streets in towns of some importance. Rendering-highway tertiary neutral.png South of Kalangba en route to Outamba-Kilimi Park.JPG
highway residential Way Used for roads in the residential areas except the major streets that interconnect with various roads (ie. primary, secondary, tertiary). Rendering-highway residential.png Ea highway residential.JPG
highway unclassified Way The roads serving for interconnection of smaller villages and hamlets. Rendering-highway unclassified.png
highway track Way 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 track.png
Paths
highway path Way Paths not large enough for cars and mainly for pedestrians, both inside and outside residential areas. Path osm.png Ea highway path.JPG

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.

Description can be more precise:
surface=asphalt
surface=cobblestone
surface=concrete

surface=ground
surface=sand
surface=gravel

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 opposite, highway=track are supposed to be unpaved by default.

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.


Value Description
excellent billiards
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.

Seasonal roads

Seasonal roads are indicated by seasonal=yes. In opposite, one can indicate that a road is usable year around with seasonal=no.

An approximative closing period can be provided with a conditional restriction [1]:
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:

River crossing

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.

For bridges :
bridge=yes
layer=1

The bridge surface, especially if different from the main road, can be indicated with surface=*. For instance, surface=metal, surface=concrete or surface=wood.

If the bridge is flood_prone, i.e. water can go other the bridge during flooding, one should add flood_prone=yes. Such bridges are usually made of concrete: surface=concrete.

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:
bridge=yes
layer=1
bicycle=no
motorcycle=no
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.

Finally, for some bridges, you should carry your own beams, one may use surface=no.

For river crossing with natural or organized ford, there are two main cases. If the crossing is exceptionally flooded (after a cyclone for instance), use flood_prone=yes. If the crossing is permanently flooded, or at least for an important part of the year, use ford=yes. surface=* will be used to indicated if the crossing is organized. Typically surface=concrete for an organized ford made of concrete.

For river crossing with boats, use:
route=ferry

Multiple Paths

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]

Some examples

Example of secondary highway tagging in Sierra Leone, West Africa.