A year after starting to discuss, with some GLR editors, improvements to the section I wrote in 2016 dealing with road type exceptions for continuity, I came up with a draft for it. There are some new examples and images where roads have been promoted to a higher type for long-distance routing, as well as reasons to do this even without supporting signage. My draft also includes information about using routing road type vs. nominal road type, and it reorganizes some of the sections of the road types article, so that all the stuff about FC and whatever is under the public roads heading, and so that the unpaved checkbox is at the end, right about other drivable roads.
This looks good. I would love to dig into some of the Continuity wording, I hope to find the time soon.
I know this focuses on continuity, but I feel like the “importance of road types” section could use a small improvement as well, since it’s not just about public road types, to say that certain other drivable road types create routing penalties and should be used with care. Any thoughts on that? Also the last sentence of that section may belong better under the “public” heading.
This idea would be helpful to explain even at an overview the special types of roads that incur penalties and briefly how in transition from one to another. As I recall I picked up this knowledge over time through mentoring and interaction but it would do well to have it reiterated in this spot. Nothing that would be a huge section, just an overview in brevity.
In the image description for the routing road type use case:
The image shows Major Highway type with the +1 routing preference. I suggest additional clarifying text that both the nominal and the routing road type have been upgraded intentionally, so that the effective road type is Freeway. This matches the “AGC” style text later saying that the effective type should match the lower of the two connected roads. However…
On that point, “pruning” is mentioned once in this page. It’s basically an absent term in the wiki otherwise, but it has practical impacts as to how many road types are set.
- Should/could we have a page or section explaining some aspects of pruning? Maybe not specific values, as those may be considered trade secrets, and are subject to change without notice.
- MH is not pruned ever, last I knew, so in the SR-435 example should the road type be left as mH and routing road type set as MH? This would contradict the “match the type” directive, but maybe that should be amended to cap at MH? If there is a reason to have it be Freeway, I would add text indicating how Freeway will behave differently than MH.
I would tend to agree, that as MH isn’t pruned, it’s not necessary to augment road type above MH.
There is a possibility that some arcane parts of the routing system might prefer Freeway a bit above MH, though, and just doing it across the board makes thinking of continuity a little bit easier.
I lean towards the former, though (no need to augment past MH). And one thing that concerns me, that I’m not sure if I’ve ever answered myself: does augmenting a MH +1 to “route as Freeway” mean that “Avoid Freeways” will avoid it? That is the only big functional difference between Freeway and MH, as far as I know.
MH+1 is not avoided as a freeway (just tested). As for a description of pruning, I originally planned a concurrent update to the routing server page and was testing pruning to correct the specific info there. I was told that staff doesn’t want us to publish numbers about that, like you say Blaine, and otherwise that page is a mess and became kind of a chore to work on, since I don’t know how much of it is true anyway.
I changed the draft to say only promote up to MH, revised the example, specified that use of routing road type is preferred (they basically made it for this) and I also proposed a section on pruning in the routing server page.
Turns out this section exists but has some outdated information. We could update it and link from road types to it. Would you like to fix the dated info?
Oh jeez, that page is almost outdated enough to be set completely on fire. Where it’s meta data for other well-understood mechanisms, it’s mostly fine, but much of the other information is inaccurate or old. “Penalty points” makes me want to apply golf analogies…
I’d probably propose instead that its relevant content be merged into the Routing Server page, and the old URL made a redirect. It has a fair number of pages referencing it, so when doing so, we’d probably want to update primary links in all places as well. Or make it a transclude. The Routing Server page also needs related tune-up work.
I don’t think we should merge it. We should fix it up instead, then maybe transclude. There is penalty info in private installations that could be gathered too.
Some of the info on penalties and routing server stuff may need to be confirmed with staff before being published. How about we move forward with my draft as it stands now, then address that stuff later?
I suggest
- Move forward with your draft as proposed.
- take an inventory of related pages and address outdated information on each in turn
- then decide on common information that can perhaps be turned into a "
transcludable"
I published my draft and also added a bullet about certain other drivable road types causing transition penalties, with the requisite links, as well as moving the intro statement about the various public road types under public roads. We can work on the penalties and routing server pages next.
Here ya go. We can still transclude it in the routing server page once published