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Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 9:41 pm
by t-bomb
It has come to my attention while trying to clean up reported issues where Waze is calling out for the driver to make a U-turn where it is not allowed that there is no way to do this, save from deleting the entire road and re-doing it as a single two-way road. See permalink: https://www.waze.com/editor/?zoom=6&lat ... s=65711637

In this situation, we have an unlimited access divided highway that was laid out in Waze as two one-way segments. The connecting road in the permalink must allow for a left turn onto US 202 southbound and the left turn must be allowed from US-202 northbound onto N. Gulph road. Since both of these turns are allowed, Waze logically deduces that the u-turn motion is allowed by making a 'left' onto the connector piece, which isn't really a road in its own right, and then another 'left' onto 202 southbound, which is in effect an illegal U-turn.

There are several of these situations along this highway alone... another exists here...
https://www.waze.com/editor/?zoom=6&lat ... s=43352326

Can a fix be incorporated to solve this issue?

Re: Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 10:53 pm
by AlanOfTheBerg
I don't particularly like it a lot, but this type of junction has been done like this before quite often. By moving the junction directly to the road being turned left onto, you can suppress the u-turn because now it is a direct junction to that next segment.

If you don't get a "turn" command from the first connection, you can edit again and follow the second image example. Notice the very short portion of the segment just before the junction which allows a right-angle turn, and therefore, a "turn" command instead of a "stay to the left..." Even without that very small section, I think without it, you still may get a turn command based on the angle I see in the top image.
suppress_uturn_dedicated_left1.jpg
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suppress_uturn_dedicated_left2.jpg
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Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 10:20 pm
by BlazeTool
Search for "mapcat bowtie" for another way to solve the problem. (But you might want to check with your AM/CM as to what the preferred way for your area is).

Re: Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 9:45 pm
by CBenson
Yes, I believe that shortening the connector by 2m to 14m will prevent the U-turns. There is some indication that the segment must be shorter than 10m, but I think 14m still works on the NA server.

Re: Need to find way to supress u-turns on divided highways

Posted: Wed Nov 14, 2012 6:47 pm
by CBenson
The support page has said 10m as far back as March. But as soon as the 10m figure was published that figure was determined to be inaccurate on the NA server.

Re: Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 10:48 pm
by gerben
CBenson wrote:Yes, I believe that shortening the connector by 2m to 14m will prevent the U-turns. There is some indication that the segment must be shorter than 10m, but I think 14m still works on the NA server.
On the ROTW server, 14 m is not short enough for sure.

Need to find way to supress u-turns on divided highways

Posted: Fri Nov 09, 2012 10:51 pm
by jasonh300
15m or shorter works on U.S. and Canada only.


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Via my iPhone 3GS.

Re: Need to find way to supress u-turns on divided highways

Posted: Thu Nov 15, 2012 12:36 am
by jasonh300
A change has taken place in NA, but it's very recent...my guess would be in the past 4 days. Previously, a *named* u-turn segment worked regardless of how short it was.

As of Saturday, while troubleshooting a route, I discovered that this is no longer the case and any u-turn segment 15m or shorter suppresses U-turns, even if it's named.

Then Sunday morning, I woke up to 2 URs where Michigan lefts were required, but Waze wouldn't route them through short U-Turn segments, that I had named "U-Turn" specifically to make them work.

They had been verified as working a few weeks after I did that work, about 4 months ago.

Re: Need to find way to supress u-turns on divided highways

Posted: Tue Nov 13, 2012 8:55 pm
by Kuhlkatz
gerben wrote:
CBenson wrote:Yes, I believe that shortening the connector by 2m to 14m will prevent the U-turns. There is some indication that the segment must be shorter than 10m, but I think 14m still works on the NA server.
On the ROTW server, 14 m is not short enough for sure.
Is it known or has anyone tested if the road type might have anything to do with the cross-segment length and allowed u-turns ? eg. Freeway types = <15m, other types = <10m or all types <10m ?

I can definitely vouch that 14m is not enough on ROTW for dualed 'Primary Street' types with a standard 'Street' crossing it. I just had a UR where I explicitly brought it down to 14m before the last update. Due to long delays on right turns, Waze suggested a u-turn about 350m further down the road across that particular 14m unnamed segment, followed with a left turn back into the originally intended delayed RH turn.

Re: Need to find way to supress u-turns on divided highways

Posted: Wed Nov 14, 2012 5:36 pm
by Kuhlkatz
If you type in 'prevent u-turns' on the support page, this is returned :
U-turns
Waze doesn't support currently u-turns.

In order to un-allow u-turns (in cases where the navigation might allow a sort of a u-turn by making to left turns) - the solution is to make the connecting segment shoter than 10 meters.

Unfortunately there isn't a way to mark a u-turn as possible.
It's the same answer at http://www.waze.com and at world.waze.com, so they definitely link back to the same info behind the scenes on this topic.

Are any of you USA folk seeing an increase in recommended u-turns after any of the recent updates to either the client or new WME. Your new infrastructure's been in place for a while now, so not sure if anything has changed on ROTW only in terms of routing calcs.
Maybe it's just getting more visible with having more users in the areas ?