Proposal:Modifiers for access tags
| This proposal has been obsoleted by Proposed features/Conditions for access tags and Proposed features/Extended conditions for access tags. |
 | A number of alternate solutions have been proposed. For a full list see Proposed_features/Advanced_access_tags. Update Oct-2012: The Conditional Restrictions proposal was approved by a majority vote. |
| Modifiers for access tags | |
|---|---|
| Proposal status: | Obsoleted (inactive) |
| Proposed by: | Tordanik |
| Tagging: | maxspeed<:modifiers>, access<:modifiers>, ...=* |
| Applies to: | * |
| Definition: | an access tag with access modifiers only applies if all conditions given as modifiers are fulfilled |
| Statistics: |
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| Draft started: | 2009-01-16 |
Many common traffic regulations cannot be tagged properly because of the lack of a comprehensive and consistent way of limiting the restrictions to certain vehicle types, road conditions or road users. This proposal defines a set of access tag modifiers together with a way of adding them to the base tag.
Overview and initial examples
The modifiers are separated from the base key with a colon (':'). If, for example, only destination traffic is allowed to use a street with the hgv vehicle category, this can be tagged as
- access:hgv = destination // note: bad example (could be expressed as hgv=destination), looking for better one ;-)
If multiple values with different modifiers are present, the most specific one that matches the current situation is used. So if the maxspeed differs depending on whether a road is wet or dry, this can be tagged as
- maxspeed = 120
- maxspeed:wet = 80
Modifiers are separated from each other using '&'. If there was an even lower maxspeed for hgv on the wet road mentioned above, this could be expressed by adding
- maxspeed:hgv&wet = 60
Modifiers
This section lists all proposed modifiers.
vehicle categories
Any vehicle category (as listed on Key:access) is a possible modifier. The access tag is then only valid for vehicles from that category.
user categories
The user categories
- private
- destination
can be used as modifiers. The access tag is then only valid for users from that category.
weather conditions
The modifier
- wet
describes that an access tag is only valid when the road is wet.
directions
- forward - access tag is only valid in way direction
- backward - access tag is only valid in way direction
(Note that is different from lane-specific information: There are ways with direction-dependent restrictions that do not have multiple lanes. There also can be multiple lanes for each direction.)
dimensions
Restrictions can be limited to vehicles with certain dimensions using
- weight <comparator> <value>
- height <comparator> <value>
- width <comparator> <value>
- length <comparator> <value>
- axleload <comparator> <value>
- draught <comparator> <value>
where <comparator> is one of '>' (more than) and '<' (less than). <value> is given as with maxweight, maxheight etc.
Example:
- maxspeed:weight>3.5=90
describes that vehicles (and animals) with a weight of more than 3.5 t must not move faster than 90 km/h.
Evaluating "conflicting" tags
- More specific information overwrites more general information (for a wet road, maxspeed:wet overwrites maxspeed).
- If there are conflicting tags without a "specificness" hierarchy, the most restrictive rule (e.g. lowest maxspeed) is to be chosen.
Notes on existing tagging
Some existing tags could be expressed with modifiers, for example
- maxweight=3.5 is equivalent to access:weight>3.5=no
- oneway=yes is equivalent to access:backward=no
- cycleway=opposite is equivalent to oneway:bicycle=no (or access:backward&bicycle=yes)
- ...
This proposal does not aim to abolish those existing tags, as the existing tags are widespread, shorter and more easy to understand.
possible extensions
- time of day, dates (similar to weight etc., but requires time format)
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