Post Reply

[Discussion] USA Road Types - Railroads (junctioning)

Post by SeveriorumPatrem
A couple of months ago, discussion on the script thread for WME Magic revealed conflicts with the WOP guidance for junctioning at-grade railroad crossings and what is actually being done out there by regions.

Specifically, I cited guidance updated in September 2018 that states that RR crossings should by default *not* have junctions.

https://wazeopedia.waze.com/wiki/USA/Ro ... s#Railroad
In specific circumstances, create junctions between drivable roads and railroads at grade crossings. Otherwise, do not junction grade crossings. The resulting elevation conflicts are acceptable.
This bullet point then has a lengthy footnote attached, which reads in part:
Adding a junction node for a grade crossing only benefits routing if both (1) between the existing junction nodes on the drivable road on either side of the grade crossing, there is at least one destination on one side of the crossing and room for cars to back up waiting on the other; and (2) the tracks support regular, scheduled train traffic. If either of these elements is missing, adding a junction node for the grade crossing will not benefit routing and may in some cases degrade routing.
From the conversations in that thread and from other informal ones I've had elsewhere and offline, this perhaps should be revisited? Almost every editor I've ever discussed this with was surprised by the change and had some concerns, but it's still hanging out there unresolved....
SeveriorumPatrem
State Manager
State Manager
Posts: 1109
Has thanked: 576 times
Been thanked: 393 times

Post by SeveriorumPatrem
jm6087 wrote:Are you wanting to discuss this in here or would it be better served to be discussed in the US Wiki forum?
Yes. Sigh. Wrong forum, sorry... can we get a topic move?
SeveriorumPatrem
State Manager
State Manager
Posts: 1109
Has thanked: 576 times
Been thanked: 393 times

Post by SeveriorumPatrem
Excellent point about RR junctioning that would create very short segments, interfering with good quality segment timing and turns data.
DwarfLord wrote:The USA guidance is definitely to junction RR grade crossings, it's just we don't do it in certain conditions where experience suggests doing so has zero or negative benefit.
This is not true. The quotes cited in the opening post are from the USA guidance. Here's the link again, for convenience: https://wazeopedia.waze.com/wiki/USA/Ro ... s#Railroad

I'm not advocating junctioning every crossing, per the short segments issue, disused spurs, etc. Still, Yigal's perspective, and the ability to better control closures, are worth trying to bring back into how we do these. At present USA guidance is to not junction except for very specific uncommon circumstances. Maybe that wasn't the intent, but that's where we are according to the Wiki. I think the issue should be revisited to take into account both points of view coming up in this thread to find a compromise between never and always, lay out the best practices accordingly, and get the Wiki updated.
SeveriorumPatrem
State Manager
State Manager
Posts: 1109
Has thanked: 576 times
Been thanked: 393 times

Post by SeveriorumPatrem
I think you're right, it comes down to misunderstanding. After reading your explanation and rereading guidance, I understand it and it is probably fine. That said, I am not the only one who interpreted it the wrong way. Still, now that I see what was intended, I can't unsee it, and I'm not sure why it was misunderstood! 8-)

As an aside, I totally loved this:
With all due respect to Yigal, this is the same company that told us to map every parking lot in the world.
:lol: :lol:
SeveriorumPatrem
State Manager
State Manager
Posts: 1109
Has thanked: 576 times
Been thanked: 393 times

Post by jm6087
voludu2 wrote:First - what's the simplest explanation we can give to newer editors to help them get RR junctioning right most of the time?
Kicking off the word smithing :D
As a general rule, you should create a junction when a railroad crosses a street at the same grade.
jm6087  
Waze Global Champs
Waze Global Champs
Posts: 5865
Answers: 3
Has thanked: 605 times
Been thanked: 1857 times

Post by jm6087
DwarfLord wrote:More than one person has told me the current wording isn't clear, and I absolutely support wordsmithing to improve that!

I think the current language resulted from a heck of a lot of frustration and despair over what had been introduced as a mass editing campaign for everywhere and always. As a result of this "everywhere and always" language our urban areas got sprayed with useless and often counterproductive junction nodes.

And, as always seems to happen in these cases, once the downsides of these new nodes became clear, the editors who had worked so hard to add them seemed to evaporate, leaving the mass cleanup to the ones who were uncomfortable about the mass campaign in the first place.

Since I (and the SF Bay Area) are still reeling from this event it's hard for me to get behind language that starts out too encouraging. Perhaps there's a good middle ground? Perhaps something like
In general, you should create a junction for grade crossings involving regular, scheduled train traffic if no other junction node is nearby. Junctioning active grade crossings near existing junction nodes, or junctioning abandoned or seldom-used grade crossings, may be counterproductive.
So I have to go look at the train schedule to determine if I should junction it?

To me, unless it creates unneeded short segments, if the track appears to be usable then I don't see an issue with creating a junction. It shouldn't matter if only one train or 10 come by in a day.
jm6087  
Waze Global Champs
Waze Global Champs
Posts: 5865
Answers: 3
Has thanked: 605 times
Been thanked: 1857 times

Post by jm6087
DwarfLord wrote: or the trains that pass do so at irregular unscheduled times, then this additional delay information gathered by Waze with respect to the train passage will be more or less meaningless. It may even degrade routing because Waze might say "there was a train here last Thursday at 9 AM, and here it is Thursday at 9 AM again! I better give the driver a different route in case that train reappears". This is one of the things the existing guidance means when it says "will not benefit routing and may in some cases degrade routing".
I guess I was not aware that a one time delay will translate into a historical delay for a segment. Does that also mean that if a bunch of cars get stuck behind a slow moving farmer, the routing will be degraded in the future just in case another slow moving farmer shows up?

Also what constitutes "at least one destination on one side of the crossing". Does the destination need to be within 100 ft, 1 mile, 100 miles?

I guess I need to see some examples of when it would not be beneficial to junction a crossing to better understand why one would not generally create a junction for grade crossings if the tracks appear to be active as opposed to only in specific circumstances (which makes it sound like it should be very rare to junction).
jm6087  
Waze Global Champs
Waze Global Champs
Posts: 5865
Answers: 3
Has thanked: 605 times
Been thanked: 1857 times

Post by jm6087
Side note: From what I remember, the primary reason we didn't use to junction RR crossing had more to do with the app routing on tracks. But that is no longer an issue.

Looking back through this thread, maybe this is where I am getting confused.
DwarfLord wrote:The USA guidance is definitely to junction RR grade crossings, it's just we don't do it in certain conditions where experience suggests doing so has zero or negative benefit.
You said that the USA guidance is definitely to junction RR grade crossings but you don't want to encourage it.
DwarfLord wrote:it's hard for me to get behind language that starts out too encouraging
With the guidance starting out as "In specific circumstances" does not say to definitely junction them. In fact, it says not to junction them under normal circumstances. Your original statement above seems to be closer to my starting of the language.
jm6087 wrote:As a general rule, you should create a junction when a railroad crosses a street at the same grade.
Taking your modification and comments into account:
DwarfLord wrote:In general, you should create a junction for grade crossings involving regular, scheduled train traffic if no other junction node is nearby. Junctioning active grade crossings near existing junction nodes, or junctioning abandoned or seldom-used grade crossings, may be counterproductive.
My new beginning language is:
In general, you should create a junction for grade crossing where the track appears to be active. Junctioning active grade crossings near existing junction nodes, or junctioning abandoned, may be counterproductive.
If a track is obviously abandoned, I would argue does it really need to be mapped anyway.
jm6087  
Waze Global Champs
Waze Global Champs
Posts: 5865
Answers: 3
Has thanked: 605 times
Been thanked: 1857 times

Post by SeveriorumPatrem
jm6087 wrote:In general, you should create a junction for grade crossing where the track appears to be active. Junctioning active grade crossings near existing junction nodes, or junctioning abandoned, may be counterproductive.
I like how this started, but the second sentence is slightly confusing since it is continuing a point that felt concluded in the first sentence. The second sentence could benefit from wordsmithing that makes it immediately obvious that it is an exception. Also, the first sentence already effectively defined that disused tracks need not be junctioned, so it might not be necessary to reiterate that point. I propose:
In general, you should create a junction for grade crossings where the track appears to be well-maintained and active. However, it is often counterproductive to junction active grade crossings that are near other existing junction nodes.
Later on down the line we can make sure to try to explain about destinations (HNs and places) on segments, and if there are none, how the need to junction is lessened.

As for the side discussion about abandoned crossings, I am very firmly in favor of mapping them for visual reference.
SeveriorumPatrem
State Manager
State Manager
Posts: 1109
Has thanked: 576 times
Been thanked: 393 times

Post by ojlaw
bump on this thread. i agree this could use some serious word smithing. i've read that footnote a few times every time i visit the page and i still don't know what it means. i've read it a few dozen times over the last year and i'm still lost. i would like to show editors a wiki that supports not junctioning every crossing, i think the wiki is trying to convey not creating short segments before an intersection but it's not clear.

there is also this thread - [Page update] Road types - Railroad viewtopic.php?f=1636&t=260728 which has background on the most recent changes in this wiki.
ojlaw
US Waze Champs
US Waze Champs
Posts: 317
Has thanked: 123 times
Been thanked: 104 times