How to tag hook turns

[philam48]

I would like to map which intersections in Melbourne currently have a ‘hook turn’. Most do in the CBD. This is where a vehicle must turn right from the left lane, and only when the road they are turning into shows a green signal. More information here: https://transport.vic.gov.au/road-and-active-transport/road-rules-and-safety/hook-turns

I cannot find any tagging guidelines on how to do this. Any ideas or guidance? If there aren’t any then happy to start a discussion.

It would be important to show exactly which way and direction this applies.

There are also intersections where bicycle hook turns are explicitly signed, even though this is technically legal at any signalised intersection in Victoria unless otherwise signed. So two more possible tags to consider.

Apologies if this has been answered or discussed before. I tried searching here and on the OSM wiki but nothing came up.

[aharvey (Andrew Harvey)]

Taking a look at the intersection at OpenStreetMap

… it looks like using turn:lanes might work.

For example on William Street coming from the south, heading north, to turn right into Bourke you can add turn:lanes=left;right|through prior to the intersection and turn:lanes=right|none inside the intersection.

Then you can say if you have a right turn lane which is followed by a none or through lane further to the right then it’s a hook turn?

Either way once something is decided here it would be great to document it at Australian Tagging Guidelines/Road Signage - OpenStreetMap Wiki

[philam48]

Thanks Andrew that looks good for mapping the physical layout for a motor vehicle hook turn. I’m not sure how this would work for mapping bike hook turn boxes though (e.g. New hook turn facility on Rathdowne Street at intersection… | Flickr or Hook turn bike box on Frome Street, Adelaide | Philip Mallis | Flickr) or a scenario like this where there is a part-time turn ban for motor vehicles but bikes are excepted only via a hook turn (e.g. 'Bicycles excepted via hook turn' sign for southbound cycl… | Flickr)

How about the turning restrictions tagging? I’m thinking a use case of routing software where it would be useful to know which intersections utilise a hook turn and which ones don’t.

And if a bicycle hook turn is banned how that would be mapped.

[aharvey (Andrew Harvey)]

@philam48

Thanks Andrew that looks good for mapping the physical layout for a motor vehicle hook turn. I’m not sure how this would work for mapping bike hook turn boxes though (e.g. New hook turn facility on Rathdowne Street at intersection… | Flickr or Hook turn bike box on Frome Street, Adelaide | Philip Mallis | Flickr) or a scenario like this where there is a part-time turn ban for motor vehicles but bikes are excepted only via a hook turn (e.g. ‘Bicycles excepted via hook turn’ sign for southbound cycl… | Flickr)

Did you see Proposal:Two-stage bicycle turn - OpenStreetMap Wiki ?

Cycle lanes can be included in lane access tagging per Lanes - OpenStreetMap Wiki so especially your first example, this could be

turn:lanes=right|through|none|none
bicycle:lanes=designated|designated|yes|yes
vehicle:lanes=no|no|yes|yes
cycleway:lanes=lane|lane|no|no

With the “hook turn” being defined as right appearing prior to through or none values in turn:lanes

@philam48

How about the turning restrictions tagging? I’m thinking a use case of routing software where it would be useful to know which intersections utilise a hook turn and which ones don’t.

The turn:lanes tagging like this is mapping the restriction, ie. which lanes you’re restricted from turning right from and which lanes you’re permitted from turning right from. A hook turn could be defined as a right value appearing left of a none or through value in the turn:lanes values. Are there any cases where either this wouldn’t be a hook turn or where a hook turn applies without this holding true?

Some routing engines already take turn:lanes into account, but likely more for providing better guidance instructions rather than influencing routing. They could use this logic to decide if a turn is via a hook turn and then influence routing based on that.

That said, I’m not sure if we should rely on this physical layout tagging for this, it could be problematic for example if the turn:lanes isn’t tagged all the way up to the intersection it may not be linked to the intersection for routing, so a relation would be more reliable.

@philam48

And if a bicycle hook turn is banned how that would be mapped.

Good point, I’m not sure about that. Does that actually happen though?

[TheSwavu (Andrew Davidson)]

@aharvey

Does that actually happen though?

Before I searched I would have said no. However R2-22 No Hook Turn By Bicycles | Transport for NSW

Never seen one in the wild.

[Robot8A (Héctor Ochoa Ortiz)]

A while ago, I saw this hook turn in Spain (I used to take a bus line that went through there a lot when I was a kid ), where it’s mapped with turn:lanes, and I believe it’s the correct approach

Way: ‪Avinguda de Madrid‬ (‪989744747‬)

In this example, the hook is there to give a big radius for buses to turn, allowing them to do a u-turn or enter the street that goes onto the bus station.

[philam48]

Thanks all for your help and apologies for the late reply.

I have implemented this schema at this one intersection in the CBD. I think this covers it but just checking if I missed anything from the discussion above? Way: ‪Elizabeth Street‬ (‪1458571609‬) | OpenStreetMap

I’ll add this into the wiki page under the different use cases discussed above.