Australian country rules

Open Source Routing Engine
1

Hi,

Is there an country rules file for Australia? When I enabled country rules, there was a list of 3-letter codes in the logs, but none looked familiar.

If not, can coutry rules change the state of all turns restricitons within a region?

For example, in New South Wales and South Australia, a U-Turn is not allowed at any intersection unless explicitly allowed. Is that something I could put into a rules file?

Thanks for all your help! If there isn’t one yet I’d be happy to have a go at it.

Cheers,
Tudor.

2

There is no country rules file for Australia, yet. Also generally the country rules cannot handle turn restrictions (yet). I’m interested in what exactly is generally forbidden in NSW and SA, see the other topic.

3

Thanks for your time!

The other topic is about working around the absence of being able to filter turns on highways (similar to u_turn_costs but on highways) which may be related to this, but I’m keen to treat the topics seperately.

This topic is about Australian country rules more generally and whether it should be in the maps dataset or implemented as a country rule.

So, in this topic, to answer your question, most states and territories in Australia have a rule like this:

40 Making a U-turn at an intersection with traffic lights

A driver must not make a U-turn at an intersection with traffic lights unless there is a U-turn permitted sign at the intersection.

Maximum penalty—20 penalty units.

Note.

Intersection and traffic lights are defined in the Dictionary.

– NSW Government, Road Rules Act 2014, Division 4 U-Turns, Clause 40
(https://legislation.nsw.gov.au/view/whole/html/inforce/2024-10-31/sl-2014-0758)

Another way to implement this would be to find every traffic light intersection in the affected state and territory and add a “No U-Turn” symbol at that intersection, even though a sign may not exist.

If that’s the preferred solution, I’d be concerned about the overhead in remembering the application of the road rules vs what’s actually evident on the road could lead to mistakes as the map data is developed and bitrot of the data.

Partly this is because this particular road rule is quite dangerous if ignored. If Graphhopper suggests to a user to follow a route then I would expect that route to be legal, at the very least. Where there is a “No U-Turn” sign that could be understandable, but where it’s a road rule with no visible prompt to the user then it’s important that the data is either correct or that there’s some other mechanism to take into account these more general regional rules when planning the route.

We’d be keen to help with this with code or testing but we don’t want to do that without first understanding the design plan for these things

Thanks again!.

4

Ok, at this stage it would be most useful to collect some examples in OSM. Are the lanes on these junctions typically separated, or are they mapped as a single way in OSM? Are these ‘u-turn permitted’-signs mapped in OSM?

5

Here is an example for an explicit no-u-turn restriction (with separated lanes) in Canberra (NSW): link

I wonder if the local OSM community decided to map such turn restrictions explicitly (despite this is the default, even without explicit traffic signs), or rather to explicitly map the exceptions to this rule (u-turn permitted), or both, or did not ‘agree’ on anything as it is often the case for OSM :slight_smile:

I found this paragraph in the wiki:

Generally, u-turn’s are not permitted at traffic signals however in some cases, you are permitted to if there is a “U-turn permitted” sign. If a sign is typically present at the traffic signals but has been removed, it is illegal to conduct a u-turn. Due to this, it is recommended that a relation uses the restriction:conditional=* tag instead of having no turn restriction at the intersection.

type=restriction
restriction:conditional=no_u_turn @ (“If the u-turn permitted sign has been removed”)

I found an example that follows this recommendation here. But overall I only found 11 (!) such cases in NSW+SA using this Overpass query. More can be found in Brisbane (Queensland). But overall I’m not sure about this practice to be honest. Also the condition “If the u-turn permitted sign has been removed” seems quite odd. How am I supposed to know if the sign has been removed? And if it isn’t known what value does this data even have?

Also implementing the “no u-turns at intersections with traffic lights” would require that all traffic lights are mapped. This does not seem to be more feasible than mapping all the no-u-turn restrictions instead (which would certainly be easier for data consumers)?

Btw I mostly looked at no-u-turn restrictions for junctions with separately mapped lanes. no-u-turn restrictions on junction nodes that are supposed to indicate that turning from one way onto the the same way are another story.