Dangerous commands / screen on Zwickauer Straße in Chemnitz/Germany
  • All happens from here http://www.openstreetmap.org/way/37289330 less than two km to western direction.

    Coming from south on Reichsstraße, voice command says go straight, then turn left, where just a turn left is right. Even more, the screen asks you to stay in the lines going straight, rather than using the lanes for turning left ...


    A little to the west on Zwickauer Straße coming from Ulmenstraße voice command is go straight, what would mean, that you end up in a building if you do so ....
    Just a few hundred meters more to the west, if you go to eastern direction and continue on Zwickauer Str. voice command is turn right and then turn left.  A simple turn left would be correct there.,,

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  • I can confirm that behaviour from other places, as split streets in conbination with turn lanes have always been an issue for Navigator. But I do not say it is the fault of Navigator.

    Look, normally when using turn lanes (e.g. here left|left|through|through;right) one assumes that the next crossing is meant. But in your case, the left|left applies to the second crossing only, whereas the other turns apply to the first one. This is very tricky, and I am unsure whether the current tagging standard is unsufficient, or the routing algorithm of Navigator.
    Suggestion: Navigator should check if any of the directions can be applied to first crossing (here: through and right due to the oneway street towards east). If not, the second crossing must be used (here: left).

  • I think that straight is across first prt of dual carriageway and left after that
    it could possibly be simplified, but it is not incorrect
  • Tomas, what about No. 2 and 3?

    No. 2: Could Navigator treat the split highways as one and turn the instruction into a left instead of straight instruction?

    No. 3 seems to be here: http://osm.org/go/0MIY4BDaU?m=&way=37289330. I suppose the first "turn right" is meant from here to there?
    @Oldie: I bet this instruction would not appear if this street was linked as secondary_link. imo it is incorrectly tagged.

  • I will take it up with programers, but it may be more dangerous to announce turn left, when it would be command to turn to the first part of carriageway - then I think users would complain
  • I have already been struggling with this from the last 2-3 map builds when working on turn:lanes and destination:lanes. This weekend I have been trying to make a reproducible case as I wanted to report this myself as well, but Oldie was ahead of me.
    If you need to take the right turn it works perfectly as you don't need to cross a junction, so there the turn:lanes functionality works fine.
    Of course when you need to go "immer gerade aus" (straight forward) it also functions fine,
    However, any time you need to go left and need to cross a one-way road segment of that road, navigator mentions that you need to go straight ahead (20-40 meters) and then left.

    I have already tried all kind of combinations of turn:lanes on the way to the turn, and also on the "mini" part of the road between the two road sections I have put turn:lane tags. (If you look in Ullie's screen captures I mean the "mini-part" between the road-segment going from left to right, and the road segment going from right to left which you want to take. That mini-part is however never taken into account. Probably because it is too short.
    I should not have done that either as it is "tagging for the renderer", in this case nav app, and it's officially against the OSM rules.

  • For the first, it is definitely wrong as Navigator commands. If you use the straight lanes, you must go straight further on into Reichsstraße. It is forbidden to turn left into Zwickauer Straße from the go straight lanes and would be extremely dangerous, if you do not use the left turn lanes. Straight and turn lanes have different traffic light signals also. Actually Zwickauer Straße is one street, two lanes in each direction and lanes separated are separated by a tramway. Actually it is one intersection, not two, as it may appear from OSM data. I have no idea, how this may be solved for a navigation software, but definitly not as Navigator does now.

    You may have a look to Google Earth for those interesections.

    ad 1.


    As you can see there, you are even guided by white marks from the left turn lanes into the right direction of Zwickauer Straße.

    ad 2.


    The driver, who uses the wrong directions lanes when turning left, should return his driving license :-o . Everybody would just give the advice "turn left into Zwickauer Straße" but "not turn left into Zwickauer Straße, but do not use the lanes of the opposite direction" in such a situation.

    ad . 3 (@Chattiewoman, you are right ;-) )


    There is nothing to turn right, imho even not to keep right. Just stay on the street up to the intersection. Even more, because the small connecting part of the opposite direction is a one way.
  • this is the problem, you solve it for one intersection and it will be wrong somewhere else
  • This answer is too simple Tomas. Do you really accept, that Navigator may cause serious accidents (at least on the intersection Reichstraße/Zwickauer Straße)? On the two other intersections it is much more obvious for a driver, how he has to drive. One will just think, what a silly software :-(
  • no, I do not accept that - navigation is a tool to help, not to follow it blindly
    driver always needs to consider the real situation
  • I agree. That's why a simple "turn left" in all situations above is acceptable for me ;-)
  • The current version of conversion ignores oneway and types of roads - I suppose that if you select pedestrian and go left against the oneway you will see green arrows ...

    The current plan is:
    1) remove wrong oriented oneway connections
    2) handle lanes:backward
    3) add neighbors of expanded junction

    ... so after first step this crossing will not show lanes arrows and after 3rd step it should work correctly (I hope).
  • step 1 completed (for December 2014 conversion)
    + I would add
    4) extend lane link to length of original OSM way (now it is cut by the first junction including footways)
  • step 2 prepared for experiment in Dec 2014
  • I have just extended the lanes,as recommended, until the actual junction node
  • @rab - I am not sure what you did (and where). It should be mapped as it is in reality. What I mean by point 4, is TODO for MapFactor, that during processing all OSM ways are first split by crossings into internal "links" and the lane information would be lost (or more precisely available only on the very last segment).
  • It is still about that particular junction in Chemitz. I have extended the lane informations  into the the junction.
    That is the more common way to map and I thought that this was recommended by you.
  • lanes=4
    left|left|through|through (???)


    @Oldie: Try disable 'Detail Navigation'.
  • @mdx
    At the moment the lanes-scheme works without any relation. Maybe all the splitted ways with turn-informations onto one crossing should packed together in one relation with the crossing-node. Would that help to show the turn lanes with all their length and solve this problem?
  • Today I got report that lanes:backward do not work properly with this (confirmed) example in Hungary:

    It is exception or the order is wrong always? (I am just curious that nobody else reported this issue sooner)

  • @mdx
    Did I get you wrong, or did you forget about my earlier report? http://forum.mapfactor.com/discussion/6059/lanesbackward-and-turnlanesbackward/p1

    What exactly do you mean with "wrong order"?
  • @chattiewoman - good point, I will switch to the other discussion. At that time we were not supporting "lanes:backward" but that changed in December 2014 - now they are supported by Navigator, but what I have seen so far they are a bit confusing even for mappers ... TO BE CONTINUED on http://forum.mapfactor.com/discussion/6059/lanesbackward-and-turnlanesbackward/p1

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