Key:hazard
 hazard
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| Description |
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A hazardous or dangerous feature. 
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| Group: hazards |
| Used on these elements |
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| Documented values: 51 |
| Useful combination |
Status: approved
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| Tools for this tag |
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A hazard is a potential source of damage to health, life, property, or any other interest of value (see 
Hazard). Hazards include natural features of the environment as well as those of human origin.
Values
The following tables describe tagging for various types of tagging.
Area hazards
This table describes values of hazard=* for areas tagged with boundary=hazard.
Traffic hazards
The following values of hazard=* are used to tag signed hazards on roadways.
If the hazard only applies in one direction of travel along the road, then use hazard:forward=* or hazard:backward=*, see Forward_&_backward,_left_&_right.
Further ad-hoc values
| Key | Value | Element | Description | Image | Usage count | |
|---|---|---|---|---|---|---|
| hazard | damaged_road | 
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A section of damaged road where it is recommended to reduce speed | 
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| hazard | traffic_signals | 
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A section of road approaching near traffic lights where it is recommended to reduce speed | 
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| hazard | roundabout |
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A section of road approaching near a roundabout where it is recommended to reduce speed | 
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| hazard | falling_trees | 
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An area or section of road that is prone to trees falling over or branches breaking off. | 
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Tagging guidelines
The hazard=* tag is intended to tag hazards that are explicitly declared by posted signage and/or government declaration. Consistent with OSM conventions, mappers should only tag hazard features that are permanent or recurring, rather than temporary.
Roadside signage
For tagging roadside signs, there are multiple possible approaches:
- Place a node adjacent to the roadway, and tag it with traffic_sign=hazard and the appropriate hazard=* tag.
- Tag a node in the roadway, with traffic_sign=hazard + hazard=* at the location adjacent to where the sign is located. If known, mappers might instead use traffic_sign=* with the specific traffic sign ID, also combined with hazard=*.
- For hazardous curves, apply hazard=curve to the
starting from the signed location and extending through the curve. - For hazards that occur along a defined stretch of roadway, apply the appropriate hazard=* to the representing the portion of the road for which the hazard applies. This should only be done where there is adequate data available to apply the hazard tagging to a stretch of roadway, such as in cases where the start and end of the hazard are signed, or when a sign indicates the oncoming distance over which the hazard occurs.
- Some combination of the above, in which both the sign and the actual hazard are tagged.
Verifiability guidelines
As with all objects and tags in the OSM database, verifiability is a prime concern. Mappers should not tag subjective hazard features that cannot be confirmed by other mappers. Hazards present an especially difficult case, since normal methods of verification (visiting the site in person) may present danger. However, there are still resources available. Examples of how hazards can be verified include:
- Hazards to drivers and pedestrians indicated by signage, including roadside signs.
- Hazards to health and safety indicated by fences or other barriers with posted signs.
- Hazardous areas as demarcated by reliable and authoritative sources.
- For example, government maps or GIS systems.
Software support
OSMAnd warns when the route traverses certain hazards.
OSRM does not yet support this key. [1]
See also
- flood_prone=* – Indicates that the feature is likely to flood after very heavy rain.
- Forward_&_backward,_left_&_right – Used to describe position or direction relative to a way