Key:source:maxspeed
 source:maxspeed
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Records the source for a speed limit, either a sign, a context (default limit) or a speedlimit zone. 
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| Group: annotations |
| Used on these elements |
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| Documented values: 9 |
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| Status: in use |
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The source:maxspeed=* tag records the source of a road's maximum speed limit as provided in the maxspeed=* tag to assist with verifiability and maintenance. This may be a sign giving a numeric maximum speed, or a 'zone' from which the appropriate numeric speed limit can be determined by knowledge of local traffic laws.
How to tag
- See also: Speed limits
- sign (where the speed limit is defined by a numeric sign.)
- markings (where the speed limit is defined by painted road markings.)
- <country_code>:<context> (where the speed limit is defined by a particular context, for example urban/rural/motorway/etc., and no maxspeed is signposted)
Do not use <country_code>:<context> where there are signs that are prescribing the same maxspeed as the default.
For a list of implicit values for this tag, see the section in maxspeed page.
Examples
An urban road in Italy would be tagged:
- maxspeed=50 and source:maxspeed=IT:urban
Where the speed limit is indicated by special speed limits signposted at the zone boundaries they can be tagged as follows:
- maxspeed=30 and zone:maxspeed=DE:30
- maxspeed=30 and source:maxspeed=DE:zone30
- maxspeed=30 and source:maxspeed=DE:zone:30
Other (less recommended) variations
- maxspeed=30 and source:maxspeed=DE:zone - Proposed by a discussion on a mailing list citation needed (used 4k times in May 2014), usage stagnating according to taginfo history (5779 as of 3/2017)
- maxspeed=30 and source:maxspeed=zone - Proposed in the discussion of this page (analogously to other not country and speed-specific values like sign and markings) (usage stagnating, 1,8k as of 3/2017)
Country-specific exceptions
In some areas, default maxspeeds are not uniform in the whole country, in these cases simply use more refined codes referring to the area.
Belgium
There are three relevant regions (different default rural or urban maxspeed), Flanders, Wallonia and Brussels-Capital Region, with these ISO codes: source:maxspeed=BE-VLG:..., source:maxspeed=BE-WAL:... and source:maxspeed=BE-BRU:.... Flanders and Brussels have a lower default rural speed limit (70 km/h) compared to Wallonia (90 km/h). The Brussels-Capital Region has a lower urban speed limit (30 km/h) compared to Flanders and Wallonia (50 km/h)[1]. Used values are found here.
United Kingdom
The U.K. community uses the key maxspeed:type=* and, in general, reserves this tag to describe how the maxspeed was determined with values comparable to the main source=*. The issue being that if source:maxspeed is used for the type of speed limit there is no tag to describe how the data were acquired. The UK has a specific sign meaning "speed restriction lifted, national speed limit applies" where the actual speed will depend on the road type (single or dual carriageway). Some U.K. use source:maxspeed=* to tag the source of the information as for other tags of the form source:*. After prolonged discussion of this point on talk-gb resulted in agreement to use source:maxspeed for the data source (survey, Open Data, etc) and maxspeed:type=* for the information described on this page. This usage is more consistent with the general pattern of tagging. It also resolved a conflict about how unsigned national speed limits should be tagged.
Note that this section applies to the United Kingdom as a whole (not Great Britain alone).
Possible tagging mistakes
See also
- maxspeed:type=* - One of two ways to specify the type of speed limit
- zone:maxspeed=* - Used to mark streets which are part of a maxspeed zone
- zone:traffic=* - Describes if a public road is in a specific trafficzone