[Tagging] Sample tagging for highways with no lane markings
61sundowner at gmail.com
Thu May 24 04:13:35 UTC 2018
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:
The metrology term is 'uncertainty' .. so
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.
Best to look at the second reference in that wikipedia page ... NPL do
> 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
> 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
>> . 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  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  to the
>> urban highway tagging examples page of the wiki  what tags
>> should it have. My current guess is:
>> For the specific example given by the photo, what tags would you
>> 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.
> Tagging mailing list
> Tagging at openstreetmap.org
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