[Tagging] Sample tagging for highways with no lane markings

[Warin]

On 24/05/18 13:47, Tod Fitch wrote:
>
>> On May 23, 2018, at 7:57 PM, Paul Johnson <baloo at ursamundi.org 
>> <mailto:baloo at ursamundi.org>> wrote:
>>
>> On Wed, May 23, 2018 at 10:34 AM, Tod Fitch <tod at fitchdesign.com 
>> <mailto:tod at fitchdesign.com>> wrote:
>>
>>
>>>     On May 22, 2018, at 12:48 PM, Paul Johnson <baloo at ursamundi.org
>>>     <mailto:baloo at ursamundi.org>> wrote:
>>>
>>>     In the case of your typical bog standard American residential
>>>     street, I'm strongly disinclined to agree that this is a two
>>>     lane situation.  I'd be inclined to mark unpainted lanes in the
>>>     cases where channelization regularly occurs without the pavement
>>>     markings anyway. This isn't the case on residential streets, as
>>>     people will tend to drive right up the middle of such streets,
>>>     only movingly right to meet oncoming traffic and maybe when
>>>     approaching a stop sign.
>>>
>>>
>>
>>     Hmmm. I guess driving culture may vary from place to place in the
>>     US. I always keep to the right regardless of the existence of a
>>     lane markings. I will admit, however, that traffic studies
>>     indicate that the average driver will be a bit more to the center
>>     of the pavement if there are no lane markings. Similarly, at
>>     least in residential areas, it has been found that drivers will
>>     generally go slower if there is no center marking. At least that
>>     is the rational my local government is using to remove the center
>>     divider marking for traffic calming purposes.
>>
>> While this may be true, most people will shy towards center (and 
>> perhaps even stay in center) for most of their trip down a standard 
>> width street (which, while typically 40 feet, this is /inclusive/ of 
>> all features including sidewalks, making the effective width of the 
>> roadway closer to 25 feet, a random pull from Mesa, Arizona's design 
>> guide <http://www.mesaaz.gov/home/showdocument?id=1044> blindly from 
>> Google confirms this, with their design guide being 27 feet across 
>> between curbs), means that two full size pickups can (barely) pass 
>> two cars parked on opposite sides of the street at once.  That's also 
>> generously wide compared to a lot of places, many suburban and small 
>> town residential streets I've encountered are open-edged with parking 
>> off the paved area, and the paved area being maybe 20 feet on a 
>> particularly wide street.  New urbanist street designs are similarly, 
>> deliberately, narrow as a traffic calming measure, as parked vehicles 
>> will tend to provide de facto ad hoc chicanes.  As such, if lanes are 
>> marked at all, it's usually at the very ends of blocks only, where 
>> parking is prohibited, as a confirmation that the street is indeed 
>> two-way and provide a hint as to the default passing rule.
>
> I have noticed that newer developments, especially infill development, 
> have narrower residential roads than where I live. And I admit I did 
> not look up current design standards. I simply took a tape measure to 
> a number of residential streets in my neighborhood. The one in front 
> of my house is 40’0" +/- 1" between the curbs. There are sidewalks but 
> I excluded them from my 40’ number. Subjectively my current street 
> seems about the same as others in the area and the same as my in 
> previous neighborhood in a different city. Both neighborhoods are 
> older, laid out when accommodating the automobile was high on the list 
> of design criteria. It would be interesting to pull out the design 
> standards that were in effect in the 1950s, 60s and 70s when much of 
> our current suburbia was created. I would not be surprised if a lot of 
> our current stock of residential roads are wider than the current 
> standards specify.
>
> By the way, I don’t see a way to tag the accuracy or confidence level 
> for a measurement. Seems like we ought to have something like 
> *:confidence=*, similar to the *:lanes tagging so we could, for 
> example tag the width of a road as:
>
> width=18’0"
> width:confidence=2’0"
The metrology term is 'uncertainty' .. so

width:uncertainty=2'0"
To be complete there would need to be a statement of level of confidence 
and coverage factor.
However, for OSM simplicity, it could be assumed to have a normal 
distribution covering one standard deviation .. making the confidence 
level ~68% and the coverage factor ~1.
Of course the stated confidence level and coverage factor would be 
assessed by the next metrologist.

There is a rough wikipedea thing on it .. it is rough. 
https://en.wikipedia.org/wiki/Measurement_uncertainty ...
Best to look at the second reference in that wikipedia page ... NPL do 
good articles.


>
> If you are only estimating from the most likely source (allowable 
> imagery) then you probably are not going to be much closer than 0.5 
> meters or a couple of feet.
>
> A confidence/accuracy tag would probably be another can of worms. How 
> are you determining it? Statistically? One sigma? Two sigma? Or assume 
> a single measurement but with a technique known to some typical error 
> pattern?
>
> But I digress.
>
>>
>>     I know that road design varies over the world and even, to a
>>     certain extent, within different states in the United States. So
>>     this discussion is showing different regional points of view. A
>>     typical, or to borrow the UK slang  “bog standard”, American
>>     suburban residential street is wide enough for parallel parking
>>     on each side and space for trucks/lorries to get past one another
>>     [1]. Typical parking lanes are about 8 feet (2.4 meters) and a
>>     typical traffic lane is 12 feet (3.7 meters). So a total pavement
>>     width is typically around 40 feet (12.2 meters). In some parts of
>>     the world, even in older crowded US cities, a road of that width
>>     might be striped for four lanes of traffic. But a typical US
>>     residential street has no lane markings.
>>
>>
>> US tends to favor 9 feet per lane and 6 or 7 foot parking strips for 
>> a full size residential street (and combine with 6 feet being the 
>> minimum, 7 becoming common, and even wider in some places for the 
>> bike lane, this will feel quite clausterphobic and many, if not most, 
>> drivers who will yield the entire space to a vehicle passing a parked 
>> vehicle first to stay out of the door zones).  Per federal 
>> guidelines, a boulevard would be at least 10, preferably 11 foot 
>> lanes (and this will still feel quite narrow to most American drivers).
>>
>>     I can see the logic of only using the lanes tag if there is paint
>>     on the pavement. But that leads to another issue: It is pretty
>>     easy from experience to glance at a photo of a road and say it is
>>     wide enough for two lanes of traffic. But it is much harder for
>>     me to determine a width accurate to a couple of feet. I don’t see
>>     a way to show a measurement error estimate [2] and listing
>>     something as width=40'0" implies much more accuracy than a guess
>>     based on a quick visual survey or imagery actually provides.
>>
>>
>> Look for the wear marks, these will be quite prominent in sun-prone 
>> areas and where concrete is used.  Generally speaking if there's 
>> defined lanes that are just worn off, there will be wear marks where 
>> passing motorists have rolled the same spot repeatedly.  This can 
>> often be confirmed with your favorite license-compatible street-level 
>> imagery or a survey.  Though if you're using JOSM and have suitably 
>> high resolution aerials available, you can use JOSM to draw a line 
>> perpendicular to the way from curbface to curbface to find the width.
>
> My current favorite license compatible street level imagery is from my 
> dash cam. :)
>
> I am considering getting another dash cam and rigging up something so 
> that it faces out a passenger side window. I figure that would be a 
> reasonable way to capture a bunch of shop details that I can’t get 
> with a forward facing camera.
>
> Fortunately, or unfortunately depending on how you look at it, the 
> lane markings in my area are kept in fairly good repair so seeing 
> where they are worn off is often not possible.
>
>>     I am rambling. To the point, if I were to add my photo [1] to the
>>     urban highway tagging examples page of the wiki [3] what tags
>>     should it have. My current guess is:
>>
>>     highway=residential
>>     parking:lane:both=parallel
>>     sidewalk=right
>>     surface=asphalt
>>     width=40'
>>
>>     For the specific example given by the photo, what tags would you
>>     suggest.
>>
>>
>> Probably closer to 34'0" wide (we're still in agreement on customary 
>> units that the inches should be included even when not necessary when 
>> tagging?), since those vehicles are narrower than a full size pickup 
>> (typ. 7 feet) and up against the curb, and so I'm reasonably sure 
>> there's not more than 22 feet between them, but more than 18 feet.  
>> I'd still leave off the lanes.
>>
>
> Only issue with fully specifying feet and inches is that it implies 
> inch level accuracy with I doubt any of our road mapping achieves. See 
> above for a digression on tagging accuracy/confidence levels.
>
> I guess the question is: Would you leave off the lanes=* regardless of 
> the width as long as there is no painted center line? If it is width 
> dependent, at what width would you add a lanes=* tag even if there was 
> no center line painted.
>
>
>
>
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