Hi all, how do you map the attached common situation in Taiwan. The direct turn is generally restricted, but scooters may turn left in two steps. We can’t only add the turn restriction. For scooter-specific routing, the routing engine needs to know about the possibility of scooters doing a two-step-turn at this crossing. Routing should also indicate it’s not a direct turn, but in two steps. How do you map this?
For example at a crossing at Zhongshan station, the current mapping is de-touring scooters/motorcycles.
Sorry for the late reply
Might have to purpose a scooters temp stop place tagging scheme
Then use detour relation which included this scooters temp stop place
Supaplex
感謝你的回覆。
Thanks for your reply.
這種轉向限制在台灣的主要路口都很常見。仔細思考過後，我認為這應該在 OSM 的更標準化層級上解決，而不是用比較像權宜之計的標註方式。你覺得如果我擬一份新的轉向限制類型的提案，這樣做有道理嗎？
This type of turn restriction is common on all major crossings in Taiwan. After thinking it through, I think this needs to be solved on a more standardized level of OSM, not with a mapping that is more of a workaround. Do you think it makes sense if I draft a proposal for a new turn restriction type?
我很ok啊，但需要更多亞洲的聲音，不然討論區多半的歐美人士，可能生活沒碰過兩段式左轉就不在意
Supaplex
目前看起來也的確沒有兩段式左轉的標示方式，不如先在這邊討論出建議的標示方式，等到真的提出 tagging proposal 的時候也在這邊通知？
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This rules also applied to other transportation mode like e-scooter (the stand up one) and bicycle in Japan. Worth to propose one.
我也認同增加更多亞洲聲音是最佳方案。然而，我希望OpenStreetMap編輯者通常會重視實地真相。若全球尚未就兩階段左轉的處理方式達成共識，台灣（或日本）的地圖便無法完全反映現實。（在此特定案例中，`restriction=no_left_turn, except=motorcycle` 雖接近要求，仍未能反映實際狀況——現實中機車在路口仍無法直接左轉。）因此我期盼即使非亞洲地區的編輯者，也能重視亞洲地圖的準確性，對這個議題保持關注⋯⋯
I also agree that having more Asian voices is best. However, I’d hope that OpenStreetMap editors usually take ground truth important. If we don’t have a global consensus on how to handle two-stage left turns, the maps in Taiwan (or Japan) cannot fully reflect reality. (In this particular case, `restriction=no_left_turn, except=motorcycle` comes close, but it still doesn’t reflect the actual situation, because in reality, scooters still cannot turn left directly at intersections.) So I hope that even editors who are not in Asia would want the maps of Asia to be accurate and have some interest in this issue …
Hi all, I’m not Taiwanese, hope you don’t mind me commenting. I saw this thread and was interested, because I’ve also been looking for ways to tag two-stage turns.
The ones I’m personally interested in are for bicycles, and located in Canada. But it looks like they might be pretty similar to yours!
I asked about tagging for this around 2019, and at the time there wasn’t a defined tagging. Several options were suggested, which I collected in Proposal:Two-stage bicycle turn - OpenStreetMap Wiki. Of those, I’ve liked the relation solution the best, so using type=restriction + restriction:bicycle=two_stage_turn_box with from, to, and via members. It’s a little inelegant, because in Canada these are mostly not restrictions, but rather extras that are technically optional to use; but I didn’t find a better option so far.
In Taiwan, do you also have two-step-turn areas for scooters where a normal left turn is allowed?
I ask because for intersections where left turn is forbidden except for scooters two-stage, you could tag something like type=restriction + restriction=no_left_turn + except=motorcycle + motorcycle=two_stage_turn. (AFAIK this wouldn’t be supported by any current routers, but I think we’ll have to first define a tagging, then ask routers to support it.)
But if there are intersections where left turn is allowed and there’s also a two-stage turn area for scooters, there is no no_left_turn restriction to attach to, so we’d have to come up with new tagging anyway.
You can also see values that mappers worldwide have used so far by searching Taginfo for “two stage” Search results | OpenStreetMap Taginfo (I didn’t find anything for “two step”)
Yes, most of the intersections are mandatory, but more are changing to an optional for scooters.
In most cases, motorcycles also had different restrictions from scooters & bicycles.