Proposal:Hazard

Hazard
Proposal status:	Voting (under way)
Proposed by:	Initial draft by Espen Adopted by ZeLonewolf
Tagging:	hazard=* Data item
Applies to:
Definition:	Hazardous or dangerous feature
Statistics:
Rendered as:
Draft started:	2007-08-28
RFC start:	2020-11-25
Vote start:	2020-12-12
Vote end:	2020-12-26

Proposal

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.

The following tagging is added:

• boundary=hazard is introduced for hazardous areas.
• traffic_sign=hazard is introduced for motorist hazards indicated by traffic signs.
• hazard=* is introduced as a new key to tag verifiable hazards, with an initial set of values as described in this proposal.
• The optional tags hazard:animal=* and hazard:species=* are introduced to further describe the type of animal or species associated with a hazard=animal_crossing. Those tags are intended to use the same value scheme used by animal=* and species=*, respectively.
• curve=* is introduced as a new key to specify the type of a dangerous curve hazard.
• curves=* is introduced as a new key to specify the type of a dangerous multiple-curve hazard.

The following tagging is deprecated:

• Redundant values of hazard=*, as listed in the tag tables.
• protect_class=16

This proposed tagging is not an exhaustive inventory of all possible hazards that might be mapped. However, it does attempt to embrace and extend existing hazard=* usages and form a foundation upon which future proposals might further define additional hazard tagging.

Background

This proposal was first developed in 2007 but was never completed. Since that time, hazard=* has achieved over 30,000 de facto usages, with the largest usage being hazard=animal_crossing, which accounts for 12,000 of those uses. As a result of this ad hoc usage, competing tag values of hazard=* have been invented. For example, both hazard=side_winds and hazard=crosswinds are in use while conveying the same meaning. In these cases, it is proposed to retain the most commonly-used values and usage patterns when multiple synonyms are in use, while formally deprecating the less-popular synonyms.

The tag protect_class=16 was invented as part of boundary=protected_area in order to describe "longtime hazard areas". With the introduction of the hazard=* key, mappers can tag hazard areas with greater granularity by specifically indicating the type of hazard that is present. Therefore, it is proposed to deprecate protect_class=16 as it is fully replaced by this key. Of note, there is strong consensus that plain-English tagging is preferred over numeric-coded protect_class values.

Proposed New Tags

The following sections describe the proposed new tagging.

New values of top-level tags

Tag	Applies to	Deprecates	Description	Taginfo
boundary=hazard		protect_class=16	The signed or designated boundary of a hazardous area.
traffic_sign=hazard			A traffic sign that indicates a hazard to motorists, for cases in which the specific code is either not known or the sign is non-standard. It remains valid to tag a more specific code in traffic_sign=* if known, for instance: traffic_sign=US:W2-2L traffic_sign=US:OH:W11-14a.

Area hazards

This table describes proposed new values of hazard=* for areas tagged with boundary=hazard.

Tag	Applies to	Image	Description	Taginfo
hazard=contamination			When used on an area, indicates an area contaminated by chemical agents. Examples include chemical dumps and former heavy-industry areas that may still be toxic. Additional usages: When combined with amenity=drinking_water, indicates a contaminated drinking water source that is still used as a drinking water source despite contamination. If the drinking water source is no longer used because of the contamination, it is not drinkable and thus amenity=drinking_water would be incorrect. When used with natural=water or waterway=*, indicates a contaminated water feature.
hazard=minefield			Active or possibly active mine fields from past or present military conflicts. This tag requires military=danger_area. If the mines are laid in a known linear pattern, this may be modeled as a . More likely, it should be modeled as an to indicate the area of a minefield in which the precise location of each mine is not known.
hazard=nuclear			An area which is contaminated with nuclear radiation. May also be tagged with military=danger_area if applicable.
hazard=shooting_range			An area near an active shooting range which has a danger of accidental gunfire. This tag is specifically meant for the signed area in which people should not enter because of the gunfire danger, and not the overall property boundary of the shooting range. If the area is a military shooting range, it should also be tagged with military=danger_area.
hazard=unexploded_ordnance			An area in which  unexploded ordnance may be present. If this hazard exists in an active military area, it should be combined with military=danger_area (and landuse=military). If this hazard exists outside of an active military area, combine it with boundary=hazard.

Traffic hazards

The following values of hazard=* are used to tag signed hazards on roadways.

New values for the key hazard=* for motorists

Tag	Applies to	Deprecates	Image	Description	Taginfo
hazard=animal_crossing Optionally combined with: hazard:animal=* hazard:species=*		hazard=cattle hazard=cow hazard=deer hazard=moose hazard=reindeer hazard=wild_animal hazard=wild_animals hazard=farm_animals		A place where animals are known to appear unexpectedly, presenting a collision hazard to motorists. This tag is optionally combined with hazard:animal=* or hazard:species=* to indicate the type of animal that is known to appear (e.g., deer, moose, livestock, etc). This tag should not be confused with man_made=wildlife_crossing, which refers to bridges, tunnels & other structures designed to allow wildlife to safely pass across a road or highway.
hazard=bump				A bump in the road which may be hazardous to motorists. This value covers both artificial bumps and natural bumps in the road that form over time as the roadway deteriorates. For speed bumps or speed tables see traffic_calming=*. Traffic calming devices themselves should not normally be tagged with hazard=bump.
hazard=children		hazard=playing_children		A place where children are known to play in the roadway, presenting a collision hazard to children and motorists.
hazard=cyclists		hazard=bicycle hazard=bicycles		An area where cyclists present a hazard to motorized, non-motorized or pedestrian traffic. This should be used for areas in which have signed warnings that cyclists may be in the roadway, or that motorists should share the road with bicycles. This tag should not be used for bicycle crossings; instead see highway=crossing + bicycle=*.
hazard=dangerous_junction				A junction or intersection that has a high rate of traffic collisions.
hazard=dip				A dip in the road which may be hazardous to motorists. This value covers both artificial dips and natural dips in the road that form over time as the roadway deteriorates. For speed dips or rumble strips, see traffic_calming=*. Traffic calming devices themselves should not normally be tagged with hazard=bump.
hazard=falling_rocks		hazard=rockfall	File:Belgium-trafficsign-a19.svg	An area in which rocks, dirt, or other natural materials may fall unexpectedly from cliffs above, or may have fallen, presenting a hazard. May be combined with natural=scree for areas in which rubble from prior falls has collected.
hazard=frost_heave				An area where the road is known to bulge because of ice underneath the roadway.
hazard=horse_riders				An area where horseback riders in the roadway present a hazard to motorized, non-motorized or pedestrian traffic. This commonly occurs in areas where horseback riders routinely transit to, from, or between bridleways. This tag should not be used for bridleway crossings. Instead use highway=crossing + horse=yes.
hazard=ice				An area where ice tends to form more frequently than surrounding areas, presenting a sudden loss of traction hazard to motorists.
hazard=landslide		hazard=rock_slide		An area where where landslides, mudslides, or rockslides are known to occur.
hazard=loose_gravel				An area along the road where rocks and stones may be present, presenting a hazard to motorists.
hazard=low_flying_aircraft		hazard=air_traffic		An area where low-flying aircraft may present a distraction hazard to motorists.
hazard=pedestrians		hazard=pedestrian		An area where pedestrians share a roadway with motor vehicles. This should not be confused with highway=crossing (), a place where pedestrians cross a roadway.
hazard=queues_likely				An area which frequently experiences a queue of cars backed up on the roadway.
hazard=school_zone				An area near a school in which special traffic laws apply. Motorists are advised via signage to reduce speed and watch for the presence of schoolchildren in the roadway. This tag should be applied to the stretch of highway=* for which the school zone applies.
hazard=side_winds		hazard=crosswinds		An area which frequently receives high winds that present a danger to people.
hazard=slippery		hazard=slippery_road		An area or stretch of roadway which is slippery, or slippery under certain conditions, presenting a hazard to motorists An area or pathway which represents a slip-and-fall hazard to pedestrians.
Curve & Turn Hazards
A curve hazard is a road which presents a risk to motorists due to sharp turns and/or obscured visibility of oncoming traffic. This tagging is applied to roads that are signed for dangerous curves and should not be applied indiscriminately to roads merely because they have curves. Tagging can be applied to the curved section of road or the location of the signage.
hazard=curve		hazard=bend hazard=dangerous_turn		Indicates that there will be a single curve in the road ahead
hazard=curve + curve=hairpin				Indicates that there will be a hairpin (180°) curve in the road ahead
hazard=curve + curve=loop				Indicates that there will be a loop (270°) curve in the road ahead
hazard=curves + curves=extended				Indicates that there is an extended section of curvy road ahead
hazard=curves + curves=serpentine				Indicates that there is a serpentine curve ahead
hazard=turn				Indicates that the road will turn sharply
hazard=turns			File:Australia W1-2 (R).svg	Indicates that the road will experience multiple sharp turns

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

Mappers should not tag subjective hazard features which cannot be confirmed or denied even when visiting the location in person. 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
• Government-declared hazardous areas as marked on government maps and/or GIS systems

The following articles are a useful reference to compare road signs between countries:

•  Comparison of European road signs
•  Comparison of traffic signs in English-speaking countries
•  Road signs in the United States
•  Road signs in Canada

Rationale

1. There is a need to tag hazards, as evidenced by the 30,000 existing usages of hazard=*. Formally adopting this key and standardizing its most popular values allows for data consumers to rely on consistent usage across the database.
2. The tag military=danger_area is often used to tag non-military hazards because that tag renders in Carto. Adopting the hazard=* key provides an approved mechanism to tag non-military hazards that renderers can reliably support.
3. Roadside hazards are verifiable via posted signage. There are vast numbers of these posted hazards on roadways across the globe.
4. There are considerable numbers of chemical and nuclear contamination sites worldwide. For example:
   1. In the United States, there are 1,344  EPA SuperFund Sites.
   2. In the European Union, there are more than 12,000  Seveso Sites
   3. In Australia, there are an estimated 160,000 contaminated soil sites.
5. For military hazards tagged with military=danger_area, this proposal gives mappers the ability to add additional specificity to the type of hazard present.
6. The cryptic numeric tag protect_class=16 does not follow the OSM convention of using English-language words to describe objects, and instead relies on a lookup table. A numbered value in this situation is confusing and unnecessary. In addition, protect_class=16 has scant usage. The protect_class=* tag as a whole is confusing and unwieldy due to this use of numeric values rather than the OSM convention of English words. Deprecating protect_class=16 improves tagging for hazards by centralizing them in one key. In common usage, the term  protected area is understood to describe preserved open space, certain types of parks, and conservation areas. The removal of hazards from boundary=protected_area further reduces the scope of that key to better reflect the plain-English meaning of that tag.
7. The voting log and result for the approved Special Economic Zone proposal shows that there is strong community consensus for replacing numeric values of protect_class=* with plain-English tagging.
8. The combination boundary=protected_area + protect_class=16 has no known use among data consumers or renderers, therefore this change has no or minimal impact on users of OSM data.
9. The new tag boundary=hazard provides a meaningful and plain-English top-level tag for area-based hazards.

Taginfo Analysis

• The use of hazard=* is overwhelmingly more popular than protect_class=16.

Current usage of hazard=*	Current usage of protect_class=16

• The use of hazard=animal_crossing is overwhelmingly more popular than various other values in this key which describe animal-based hazards. The values used by the existing animal=*/species=* keys provide a mechanism for further clarifying the type of animal via hazard:animal=* and hazard:species=*. This avoid the need for endless animal-specific variants of hazard=animal_crossing.

Current usage of hazard=animal_crossing	Current usage of hazard=cattle	Current usage of hazard=cow	Current usage of hazard=deer
Current usage of hazard=moose	Current usage of hazard=reindeer	Current usage of hazard=wild_animal	Current usage of hazard=wild_animals

• The use of cyclists=* is more popular than the alternatives hazard=bicycle and hazard=bicycles.

Current usage of hazard=cyclists	Current usage of hazard=bicycle	Current usage of hazard=bicycles

• The use of hazard=children is significantly more popular than hazard=playing_children, and they are essentially describing the same thing: the potential presence of children in the roadway.

Current usage of hazard=children	Current usage of hazard=playing_children

• The use of hazard=curve is more popular than hazard=bend or hazard=dangerous_turn, and they are essentially describing the same thing: an upcoming stretch of road that is challenging due to curvature. Since hazard=curve has the most popular usage, hazard=turn and hazard=turns are introduced in order to maintain consistence in naming convention with this most popular usage.

Current usage of hazard=curve	Current usage of hazard=bend	Current usage of hazard=dangerous_turn

• The use of hazard=falling_rocks is less popular than hazard=rockfall. However, discussion on the tagging mailing list revealed a preference for "falling rocks", which is the usual English-language text found on signs for this hazard.

Current usage of hazard=falling_rocks	Current usage of hazard=rockfall

• The use of hazard=landslide is less popular than hazard=rock_slide. However, discussion on the tagging mailing list revealed a preference for "landslide", which is a more general category that also includes mudslides and rockslides.

Current usage of hazard=landslide	Current usage of hazard=rock_slide

• The use of hazard=pedestrians is more popular than the plural hazard=pedestrian.

Current usage of hazard=pedestrians	Current usage of hazard=pedestrian

• The use of hazard=side_winds is more popular than hazard=crosswinds, and they are essentially describing the same thing: a stretch of road or area where high winds presents a hazard to motorists or pedestrians.

Current usage of hazard=side_winds	Current usage of hazard=crosswinds

• The use of hazard=low_flying_aircraft is less popular than hazard=air_traffic, however, mailing list discussions revealed a preference for hazard=low_flying_aircraft as the better descriptor.

Current usage of hazard=low_flying_aircraft	Current usage of hazard=air_traffic

• Although the use of hazard=slippery is slightly less popular than hazard=slippery_road, the use of "_road" as a suffix for hazard values is not used as a naming convention for other values in existing usages of key. In order to keep the naming convention consistent, it is proposed to standardize on the simpler hazard=slippery.

Current usage of hazard=slippery	Current usage of hazard=slippery_road

Examples

• 

  A moose crossing area
  (traffic_sign=hazard + hazard=animal_crossing + hazard:animal=moose)

• 

  A generic farm animal warning sign (not specifically about cows)
  traffic_sign=hazard + hazard=animal_crossing + hazard:animal=farm_animals

• 

  A sign warning of crossing cyclists in Germany.
  traff_sign=hazard + highway=crossing + hazard=bicycle

• 

  A sign warning people that children play around here at a small local children's daycare in the Groninger city of Winschoten, Oldambt, The Netherlands.
  (traffic_sign=hazard + hazard=children)

• 

  A contaminated area
  (boundary=hazard + hazard=contamination)

• 

  Curvy road warning sign with speed suggestion on Quebec Route 105 in Canada
  (traffic_sign=hazard + hazard=curves + curves=extended + maxspeed:advisory=75)

• 

  Dangerous intersection ahead, Shiga Prefecture, Japan
  (traffic_sign=hazard + hazard=dangerous_junction)

• 

  Minefield in the Golan Heights
  (landuse=military + military=danger_area + hazard=minefield)

• 

  Sign at the entrance to the Chernobyl Exclusion Zone, Ukraine
  (boundary=hazard + hazard=nuclear)

• 

  Rockslide warning at the Bisse du Ro, Canton Valais, Switzerland
  (traffic_sign=hazard + hazard=landslide)

• 

  A school zone in Australia
  (traffic_sign=hazard + hazard=school_zone)

• 

  A shooting range warning sign in the UK
  (boundary=hazard + hazard=shooting_range)

• 

  A high winds warning sign in South Dakota, United States
  (traffic_sign=hazard + hazard=side_winds)

Applies to

Rendering

• For military hazard areas dual-tagged with landuse=military and/or military=danger_area, the rendering of the military area should take precedence.
• For other hazards applied to areas, renderers should consider red or brown hatching for the area of the hazard.
• For hazards applied to a stretch of roadway, renders may consider one or both of the following strategies:
  • Apply an outline or highlight to the road segment where the hazard is tagged.
  • Display a graphical icon at either end of the hazardous stretch of road.
• For hazards applied to a , renderers should consider the use of icons that are consistent national-standard road signs. Alternately, renderers might consider a more generic graphical icon, such as .

Features/Pages affected

Page	Action
hazard=*	Create this page
hazard=animal_crossing hazard=bump hazard=children hazard=cyclists hazard=contamination hazard=curve hazard=curves hazard=dip hazard=dangerous_junction hazard=falling_rocks hazard=frost_heave hazard=horse_riders hazard=ice hazard=landslide hazard=loose_gravel hazard=low_flying_aircraft hazard=minefield hazard=nuclear hazard=pedestrians hazard=queues_likely hazard=school_zone hazard=shooting_range hazard=side_winds hazard=slippery hazard=turn hazard=turns hazard=unexploded_ordnance	Create this page
hazard:animal=* hazard:species=*	Create this page
curve=* curves=*	Create this page
curve=hairpin curve=loop curve=serpentine	Create this page
hazard=air_traffic hazard=bend hazard=bicycle hazard=bicycles hazard=cattle hazard=cow hazard=crosswinds hazard=dangerous_turn hazard=deer hazard=moose hazard=pedestrian hazard=playing_children hazard=reindeer hazard=rockfall hazard=rock_slide hazard=slippery_road hazard=wild_animal hazard=wild_animals hazard=farm_animals	Mark these tags as deprecated
Template:Protect_class	Mark protect_class=16 as deprecated
boundary=*	Update this page to add boundary=hazard as a permissible value
traffic_sign=*	Update this page to add traffic_sign=hazard as a permissible value
military=danger_area	Update this page to add applicable hazard=* values as ancillary tags
animal=*	Update this page to add association with hazard:animal=*
species=*	Update this page to add association with hazard:species=*
natural=scree	Update this page to note the potential addition of hazard=falling_rocks for a posted falling rocks hazard.

External discussions

• November 2020 Official Request for Comments Thread
• December 2020 hazard discussions
  • hazard RFC followup thread

• Tagging mailing list
  • Nov 2016 - Proper way to tag highways located in "dangerous" areas
  • Jan 2018 - Water source types
  • Sep 2019 - How to tag flood prone points and areas?
  • Nov 2019 - How to tag Seveso sites?
  • May 2020 - Doorzone bicycle lanes

• Talk mailing list
  • Feb 2018 - Highway=trunk : harmonization between countries ?
  • Jan 2020 - no-go-areas

• Talk-Italy mailing list
  • Apr 2017 - incrocio con luci gialli lampeggianti
  • Aug 2018 - Sentiero non percorribile

• OSM World Discord Server
  • 12/12/2020 Voting starting and problems with traffic signs

• Approved proposal to remove narrow from the width=* key.

Comments

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• I approve this proposal. I support a tagging scheme for hazards --ZeLonewolf (talk) 16:38, 12 December 2020 (UTC)
• I approve this proposal. --Vakonof (talk) 17:07, 12 December 2020 (UTC)
• I approve this proposal. --Lectrician1 (talk) 17:10, 12 December 2020 (UTC)
• I approve this proposal. --Rassilon (talk) 18:32, 12 December 2020 (UTC)
• I approve this proposal. --Arlo James Barnes (talk) 18:37, 12 December 2020 (UTC)
• I approve this proposal. While the richness of the subject of hazards will doubtless grow into the future, this proposal is a solid foundation for the syntax of both today and tomorrow. --Stevea (talk) 18:47, 12 December 2020 (UTC)
• I approve this proposal. --Francians (talk) 19:33, 12 December 2020 (UTC)
• I approve this proposal. --Carnildo (talk) 20:43, 12 December 2020 (UTC)
• I approve this proposal. --Mateusz Konieczny (talk) 21:00, 12 December 2020 (UTC)
• I approve this proposal. --Woazboat (talk) 21:43, 12 December 2020 (UTC)
• I approve this proposal. --Gendy54 (talk) 21:50, 12 December 2020 (UTC)
• I approve this proposal. Fantastic job, Brian. Thanks! --Fizzie41 (talk) 22:28, 12 December 2020 (UTC)
• I approve this proposal. --Brian de Ford (talk) 23:05, 12 December 2020 (UTC)
• I approve this proposal. Excellent work! Impressive. --Dr Centerline (talk) 00:09, 13 December 2020 (UTC)
• I approve this proposal. Fanfouer (talk) 00:37, 13 December 2020 (UTC)
• I approve this proposal. --Wulf4096 (talk) 12:50, 13 December 2020 (UTC)
• I approve this proposal. --Kioska Journo 14:55, 13 December 2020 (UTC)
• I approve this proposal. --Adamfranco (talk) 01:00, 14 December 2020 (UTC)
• I approve this proposal. --Russdeffner (talk) 13:16, 14 December 2020 (UTC)
• I approve this proposal. --Mapper999 (talk) 20:59, 14 December 2020 (UTC)