qwaletee wrote:if an AGC connects segments with three different types, do we have specific guidance? The general rule:

>> The connector segment's type should be set based on the lowest of the types of roads it connects.

Seems to imply take the lowest of three, but it may not have anticipated all cases of three types. Do we take into account primary use, prevalent connections, count or discount transitions of road type that HAPPEN to take place at the junction with the AGC?

Look at this example: https://www.waze.com/editor/?env=usa&lo ... s=32170542

It is basically a two-way AGC, with three road types connected.

It seems like that should be mH, to provide continuity. Maybe the AGC needs to follow the same guidance for type as roundabouts. The lower of the highest two connected segments.

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qwaletee wrote:So the second highest? That's an interesting calculus. How do we arrive at that?

It's the same methodology used for roundabouts, it works here to as that would leave us at mH.

The basic premise is we don't want the type to be low enough that effects routing by virtues of preference or pruning. Since we don't have exact metrics on how long a segment must be to cause an effect, IMHO is best to avoid the situation entirely.

The only way segment type has am effect on routing is if it cause a route to be penalized by going taking it through a lower type than it was already using. By connecting two segments, e.g. mH>AGC>MH, we used the list type present (mH) because it looked better, AND it wouldn't affect routing being that it didn't lower the type beyond the lowest already being used at the junction. In a case with more that two connected segments, we must consider the same principle, what is the lowest type we can make this segment without causing any route over it to be penalized extra.

Let's take this as an example you can route into this AGC from/to mH, MH, and PS. If we made it the lowest (PS), then routes from MH>PS>mH are penalized extra. There's no need for it to be the highest type (MH) because any route involving the MH is already transitioning from/to at least mH. So we are left with the lower of the highest two type segments which can route through the AGC. If two of the segments were MH and others were lower (mH, or PS...) then it should be set to MH so as not to penalized the route between those two MH segments.

With the description of median U-turn segments which only connect two sides of a split road. Those have their own guidance to be street or ramp depending on their situation.

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EDIT: To clarify as sketch pointed out while i was typing, I meant the lower type of the two highest type segments connected, which could be MH if the AGC connected to MH, MH, mH for example.

qwaletee wrote:I am talking about Roundabouts for the moment, not AGCs, but only because you brought it up [/i

I understand the continuity issue, but you said something a little different than that. That rationale you just stated doesn't lead to "lowest of the top two," in your previous post. In some cases it might -- if you assume that MH and Fwy are mostly equivalent, then a roundabout that connects Fwy, MH and mH (never!) could indeed use MH, since it is not perceived to be a problem, whereas mH is perceived to be a problem. So that would leave MH and Fwy, and MH is the lower of those two.

But say it connected MH, PS and Street (which is actually a reasonable combination given FC). There, the lower of the top two, PS, is a significant continuity issue compared to MH, so why would you choose the lower of the upper two? I would think you would need to use MH to ensure continuity, i.e., the absolute highest.

Because in your example of MH PS and street the only routes through the AGC from the MH are to a PS or a street. So having the AGC as PS didn't add any penalty. If what you meant is the AGC connects two MH segments, say on either side, and a PS, and street, then the lower type of the two highest segments would be MH.

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Keep in mind an AGC set with a shallow angle (stay) going from a highway (mH, MH, FWY) to a non- highway for a right turn, will give an exit instruction. If that seems wrong and will confuse wazers, a dogleg should be used to generate a turn instruction.

Now considering that this style AGC sole purpose is to deviate from the roadway, or give an earlier prompt (it is no longer changing the actual word used in the instruction), if those purposes are not needed (commitment point <50m, OR not a far actual separation point) the AGC serves no useful purpose and can probably go.

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CBenson wrote:As with most of the intersection related questions, I'm inclined to not to worry too much about adjusting guidance until we see what the long awaited "junction box" may be.

I have the same impression as sketch that the timing of the final turn instruction depends on speed rather than road type.

PesachZ wrote:Keep in mind an AGC set with a shallow angle (stay) going from a highway (mH, MH, FWY) to a non- highway for a right turn, will give an exit instruction. If that seems wrong and will confuse wazers, a dogleg should be used to generate a turn instruction.

While I understand the logic here, I'm not sure that users aren't also confused by early "turn" instructions, which seems to be part of the reason for DwarfLords post.

DwarfLord wrote:

shawndoc wrote:I would like to...remove the bolded section: "There are only a few situations in which connectors are called for in an intersection: When you get an automated report (map problem) that the roads are too far apart due to the intersection being too far from the turn lane." As written, we'd be adding turn lanes to just about any decently sized intersection that uses a mapcat bowtie. I feel the rest of the reasons listed for adding a turn lane cover the times when a turn lane is needed. The MPs about roads being too far apart have too many false positives to be used as a justification by itself to add a turn lane.

Based on the "thanks" this post received, there's apparently consensus that even a junction that throws missing-road MPs does not qualify for an AGCs based on that behavior alone. To me this says that the distance the turn path strays from mapped segments while cutting the corner should not be a factor when deciding to map an AGC. The physical presence of a dedicated ramp-like connector would be a factor! As would the presence of other nearby segments to which the driver turning could be snapped by mistake. But distance all by itself would not be a factor.

I agree based on the properties of the waze experience that we as editors can actually control. But what this doesn't take into account is any reasoning waze has for when the missing road road MPs are triggered. If the MPs are indicating that waze can't properly calculate turn times because the turns are too far from the intersection, then maybe we should give more weight to the MPs. However, this is something the waze staff should let us know. The only things I've heard on the subject from waze staff is to wait for the "junction box."

I not in disagreement with you, just showing how the stay instruction isn't always a good reason to keep an AGC either. I wait with baited breath for the junction box, however if he's already making changes and upgrading the area, I feel (without having looked myself, just based off this discussion) that a lot of them could go away.

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DwarfLord wrote:I updated the figure to add the clarification but although I see the updated image in the preview -- and I even see it in the history at the bottom of the page as I write this! -- it seems to be invisible in the thread (the forum code is finicky about images, isn't it...?). Here it is again.

AGC-question-revised.jpg

(EDIT: oooookay, now that I post this the revised image does appear in my earlier post. Rather than remove this instance and potentially break things again I'll leave it. Sorry for the redundancy.)

can you provide a PL to this AGC please?

Same road type as departing road:

PRO: Alleviates confusion to the group of drivers who would not expect to hear "turn" or "exit" at that junction.
CON: Looks sloppy in the client when the connected is of a lower type, particularly if its more than one level lower. Looks particularly sloppy at wider zoom levels if the connected road is a street, parking lot, or private road, when such a road would disappear from view.

Personally, since I pretty always only use Waze in the 3D view with auto-zoom, I'm perfectly happy with the word "turn" for any AGC where the word "exit" wouldn't be appropriate if it means we can avoid sloppy-looking graphics.

I also personally don't care about getting an instruction to keep/turn/exit/etc. at the point where a solid line begins for a dedicated turn lane. Such an announcement falsely gives the impression that individual lane guidance is available, when it is in fact not. Most of the time, Waze even has to guess which roadway of a dual-roadway highway you're on! However, many people do find this useful, so to reach a better balance between that and avoiding map clutter, I'd be ok with a 50m rule, meaning that if the beginning of a dedicated turn lane, or the AGC itself, is set back from the center of the intersection proper at least 50m (~150 ft), we can include an AGC. Distances of less than 50m are actually trivial to Waze and AGCs entirely within that range amount to just noise on the map. Conveniently, WME provides us a map scale in the lower right-hand corner to help us judge such distances at various zoom levels.

I just remember a conversation with someone way back when mentioning that distances less than 50m are trivial to Waze. I could be wrong, and the whole argument falls apart, I guess, if I am.

The amount of time you need to get into the correct lane for a turn depends on how many lanes there are and how dense the traffic is. If there's only 2 lanes and traffic is relatively right, 15 seconds, even 10 seconds, is plenty of time. If there's 3 or 4 lanes you're absent-mindedly caught in the left lane at the quarter mile warning, not so much.

Hell, there are places near my house on the Garden State Pkwy, with its 6 lanes and heavy traffic, that a 2 mile warning with well over a minute ahead of your exit might not be enough to get over from the leftmost lane.

If there is a 100m (just for example) dedicated turn lane that leads right up to the proper intersection with just a single, solid white line on a road with 3 or more lanes going through, we definitely need to provide some kind of "keep" announcement at the dedicated lane's commitment point, mainly for the purpose of getting more timely advanced cues for the driver to get into the correct lane before the commitment point, especially if the driver is in the far lane and heavier traffic makes it take longer than a few seconds to get across.

The more questionable part here is when you finally get to the intersection proper in the dedicated turn lane, do we still need a " turn" announcement there, since the lane (road) you've entered only allows the turn and no other direction.

What I was saying earlier is that I'm not sure whether an AGC is necessary at all, when only 1 or 2 lanes go through and a turn lane's commitment point is less than 50m from a point at the center of the intersection.

russblau wrote:I don't understand why "in 0.2 miles, take a right at Highland Street" is not enough to alert the driver that they should move into the dedicated turn lane.

Because if there's 4 lanes to cross on a 50-mph road to get into that turn lane before the solid white lines starts, the 0.2-mile (roughly, 1000-ft) warning is nowhere near enough time for a driver to get over from the leftmost lane.

Like I said, on a road with only 1 or 2 through lanes, it's not as big of a deal. But on road with 3 or more lanes, particularly ones with heavy traffic, it becomes much more of a problem.