Vote for intercity highways description changes

[nitinatsangsit (Nithinat)]

From https://forum.openstreetmap.org/viewtopic.php?pid=862397#p862397, I think I should make it easier for everyone to make a decision.

The goal is to improve Thailand OSM road classification consistency and make guidelines more objective by not requiring too many map changes.

Do you agree with the following:

1. Change trunk description from

Trunk classification should be applied to region’s top-level road network (apart from motorways), which connects numerous cities and is usually dual carriageway.
Most, but not all, of the 1-2-digit national highways are trunk.

to

• All 1-2-digit national highways, unless otherwise stated.
• Any other road that is 90% dual-carriageway with a physical median and shoulder and is longer than 100km. (length counting can be extended to different road ref.)
  (Noted that a 1-2-digit national highway that is shorter than 5km and is a hanging end shall be downgraded to eliminate the hanging end or to secondary.)

2. Change primary description from

Primary roads are built for long-distance travel, typically beyond province borders.
Most, but not all, of the 3-digit national highways are primary.

to

• All 3-digit national highways, unless otherwise stated.
• Any other road that is 90% dual-carriageway, has a physical or painted median (wider than 1m, not just a double solid line) and shoulder, and is longer than 25km. (length counting can be extended to different road ref.)
  (Noted that a 3-digit national highway that is shorter than 5km and is a hanging end shall be downgraded to eliminate the hanging end or to secondary.)

3. Change secondary description from

Secondary roads are major roads inside a province.
Most 4-digit national highways are secondary, however they can be primary or tertiary depending on their importance in the road network.
The high importance rural roads, which are on the same level as a 4-digit national highway in the road network, are also secondary.

to

• All 4-digit national highways, unless otherwise stated.
• A rural road or local road that is of equal or greater importance (in terms of performance/width/number of traffic lights/total length) as nearby secondary roads.

4. Change tertiary description from

Tertiary roads connect two or more villages/hamlets.
Note that the Rural Road classification is based on authority rather than importance. They might be classified as secondary or tertiary depending on their importance.
Some of the roads on this level are managed by a Local Administrative Organization. They are also tertiary regardless of an authority.

to

• All rural roads, unless otherwise stated.
• A local road that is of equal or greater importance (in terms of performance/width/number of traffic lights/total length) as nearby tertiary roads.

5. Add to the note below table

• The road section that has been rebuilt as a new route and the previous route ref have not yet been changed, hence the old route shall be downgraded 1 step.
• If two nearby roads with the same or nearby origin and end have different ranks, and the road with the lower rank has better performance (travels faster between those two points) than the road with the higher rank, their ranks shall be swapped (not just downgrade or upgrade one of them). This is usually the case with bypass roads.

The principle and rationale for these can be found in the link above.

Best Regards

[julcnx]

I like it, it’s a lot clearer now.

@nitinatsangsit

4. Change tertiary description to

• All rural roads, unless otherwise stated.
• A local road that is of equal or greater importance (in terms of performance/width/number of traffic lights/total length) as nearby tertiary roads.

Would that mean that local roads now become by default unclassified? Currently, their wiki baseline is tertiary.

2. Change primary description to

• All 3-digit national highways, unless otherwise stated.
• Any other road that is 90% dual-carriageway, has a physical or painted median (wider than 1m, not just a double solid line) and shoulder, and is longer than 25km. (length counting can be extended to different road ref.)
  (Noted that a 3-digit national highway that is shorter than 5km and is a hanging end shall be downgraded to eliminate the hanging end or to secondary.)

So a tertiary or even an unclassified baseline could become primary? I would have expected upgrades/downgrades limited to 1 level, but this would mean 2 or more…

[nitinatsangsit (Nithinat)]

Thanks for comment.

@cmoffroad

Would that mean that local roads now become by default unclassified? Currently, their wiki baseline is tertiary.

Yes, the current wiki is confusing; I wrote this way since the term “Local Road” just indicates it is maintained by the local administrative organization, so it can be tagged as tertiary or unclassified depending on its importance. However, because most local roads are more unclassified than tertiary, setting unclassified as their baseline would be simpler, and upgrading them to higher rank would be an exception owing to their importance in comparison to that rank’s road.

@cmoffroad

So a tertiary or even an unclassified baseline could become primary? I would have expected upgrades/downgrades limited to 1 level, but this would mean 2 or more…

I’d say yes. I don’t think we should be too tight with the baseline. Of course, the ref is the best thing we have for general guidelines, or in other words, the beginning of classification, and it is our stronghold for something ambiguous. By the way, I believe the physical criteria I’ve set are only for the road that is “clear enough” that it is high important. If their importance is not obvious, I’ll give the benefit of the doubt, in this case, to the ref.

As I quickly checked, very few roads would fall under the 2-step upgrade (and maybe no 2-step downgrade). It seems like only 3 rural roads appear to be tagged as primary (not including urban roads and bypass swap cases): นบ.3021, สค.1018 (together with connected national highways), and ชร.1063. When comparing these rural roads to nearby 4-digit national highways such as 3215, 3414, and 1209, it is clear that these rural roads are more important than those national highways, as well as several 3-digit national highways. So, limiting the level change from the baseline just because of the road owner may not be appropriate. If we assume that these roads will be transferred to the DOH, they will surely be 3-digit national highways.

So, I think the guidelines would be like: if it meets either 1) ref 2) characteristics, it is qualified for that rank; and if it meets the 3) other characteristics, it is disqualified.

Also, I like your ideas posted at the other topics, particularly the table rearranging. As per your recommendation, I would use multiple columns. I also think the source and note tags are a good idea, however they may not be necessary to tag it to all roads that utilize characteristics for tagging. We can use it for certain of those that are ambiguous or frequently fall to vandalism or edit wars. By the way, I would mention it in changeset comments.

[nitinatsangsit (Nithinat)]

I’m happy to report that I’ve already edited the table on the wiki, as well as the map data on trunk and primary to match the wiki.

No more headaches on trunk and primary. I’ll then tidy up the secondary highways.

By the way, I’m still open to any arguments. If you wish to change some of the rules, please leave a comment.

Happy Mapping!