[Tagging] US Speed Limits, truck routes, bike routes, access

Alan Mintz Alan_Mintz+OSM at Earthlink.Net
Fri Feb 26 22:32:20 GMT 2010


Several issues with relation to speed limits:

1. How should one tag "suggested" speeds (usually around curves) like 
http://en.wikipedia.org/wiki/File:MUTCD_W1-4.svg with 
http://en.wikipedia.org/wiki/File:Advisory_Curve_Speed_English_25.svg ? 
Should I tag them as maxspeed=*? I can see being cited for exceeding it 
according to the blanket "safe speed" provisions in some vehicle codes[1].


2. I've been tagging 25 mph school zones 
(http://upload.wikimedia.org/wikipedia/commons/d/db/SchoolZone-SpeedLimitSignAndLight.JPG) 
as "maxspeed:children_present=25 mph". Can someone comment on where such 
zones end (I realize this may, again, be jurisdiction-dependent)? I 
sometimes, but not always, see an "End School Zone" sign (should I tag 
these, and how?).


3. Based on the recent conversation about source:*=*, when I tag a way with 
maxspeed=*, I've been adding source:maxspeed and source_ref:maxspeed as 
well. Example:

- I photograph (ref1) a speed limit sign at point A, saying 40 mph.
- I create a node on the curb of the road at point A, tagged:
maxspeed=40 mph
source=survey;image;usgs_imagery [2]
source_ref=ref1

- I photograph (ref2) the very next speed limit sign I see - at point B, 
saying 35 mph.
- I create a node on the curb of the road at point B, tagged:
maxspeed=35 mph
source=survey;image;usgs_imagery [2]
source_ref=ref2

- I split the way so that I have a segment between point A and B.
- I tag the segment:
maxspeed=40 mph
source:maxspeed=survey;image
source_ref:maxspeed=ref1;ref2

If I see additional identical speed-limit signs along the way, I tag the 
nodes, but do not split the way. I tag the way with the refs for the 
endpoints only.


4. Similarly, for school zones, I'm tagging the ways:
maxspeed:children_present=25 mph
source:maxspeed_children_present=survey;image
source_ref:maxspeed_children_present=ref1;ref2

I changed the ":" to "_", not being sure if we want to deal with multiple 
levels of children.


5. For separate limits for trucks, I'm using:
maxspeed:hgv=*
source:maxspeed_hgv=*
source_ref:maxspeed_hgv=*


6. For separate limits for towing/towed vehicles, I'm using:
maxspeed:towing=*
source:maxspeed_towing=*
source_ref:maxspeed_towing=*

In CA, the standard speed limit on freeways is 65mph normally, but 55mph 
for trucks and towing/towed vehicles. This results in 9 tags(!), providing 
more reason for some sort of scheme like maxspeed=freeway.


7. Similarly, for truck routes, I create a node for the signs, tagged:
hgv=designated
source=survey;image;usgs_imagery
source_ref=ref1

and tag the ways:
hgv=designated
source:hgv=survey;image
source_ref:hgv=ref1

For bike routes, the same, replacing hgv with bicycle.


8. In rural areas especially, there is often confusion between county 
records, existing databases (e.g. TIGER, TeleAtlas), and posted signs, as 
to what portion of a road is considered "private". This is an area where I 
believe OSM and actual in-person surveying has the potential for great 
value over other maps. I'd like to create a node where I first see a "No 
Trespassing" sign (http://en.wikipedia.org/wiki/File:No_trespassing_sign.jpg).

Should I tag the node access=private [+source=* +source_ref=*]? I'll note 
that JOSM has an icon for access=no, but not access=private. I can then tag 
the way with source:access=* +source_ref:access=*.



Notes:

[1]That is, holding that the sign states what is taken to be the prima 
facie safe speed. Any traffic court judges here?

[2]survey because I saw it, image because I photographed it, and 
usgs_imagery because I used it to find the curb.

--
Alan Mintz <Alan_Mintz+OSM at Earthlink.net>





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