Roads under construction

[1ec5]

The style should show roads that are under construction and possibly some major proposed roads. Otherwise, there can be prominent, otherwise inexplicable gaps or dangling roads.

Québec Autoroute 35 is being built in phases.

This bridge across the Ohio River has been closed for repairs long enough to be tagged as being under construction too.

Precedents

The predominant convention among North American maps is to depict a road under construction as a broken line:

This convention extends to maps published in Canada or for tourists from continental Europe:

The essence of this treatment is that the casing is also broken, not just the fill, and the fill has alternating transparent segments, not white segments. I prefer this treatment to what openstreetmap-carto does, which evokes a barber pole or candy cane:

In many cases, inaccessible or unpaved roads get almost the same treatment. It seems the general idea is for a broken or dashed line to warn of a bad day:

Some maps call them “future” roads and include roads still in aspirational planning stages, while others distinguish between proposed roads and roads under construction:

The Ohio Department of Transportation at one point used a translucent red dotted overlay to indicate future roads, just like openstreetmap-carto’s access=no treatment:

Most maps in my collection, even city-scale maps only show limited-access highways under construction but omit less important roads under construction:

This could be because they only depict freeways for which a right of way has already been cleared, leaving a major gap. But it could also be because smaller roads tend to get completed more rapidly than paper maps can reliably keep up with.

Some maps do show multiple levels of roads under construction; these maps generally don’t already use dashes to convey surface conditions:

I think it would benefit mappers if Americana shows any road under construction, regardless of classification, but if the complexity of supporting yet another facet of road classification proves too complex, at least there would be precedent for only showing the most major construction projects.

Since not-yet-completed freeways are relatively rare, most maps annotate them with a special label explicitly stating that they’re planned or under construction, even giving an expected date of completion if the DOT is confident enough about it:

[matkoniecz]

I would suggest avoiding display of roads that are just proposed - it encourages mapping them and it is often filled with overenthusiastic plans, blatant campaign promises, mapping several variants, mapping personal fantasies and so on.

Completely absurd projects are being mapped.

What worse, verifying it is not really easy as you cannot just check on the ground situation and need to discuss whether project is real.

[ZeLonewolf]

Let's scope this issue to under-construction roads, which are non-controversial and supported by OpenMapTiles. Any discussion of proposed roads should be a separate ticket. I tend to agree that proposed roads have a pretty serious curation issue that would need to be explored if there is ever a serious initiative to render them.

[1ec5]

it encourages mapping them and it is often filled with overenthusiastic plans, blatant campaign promises, mapping several variants, mapping personal fantasies and so on.

Incentives can flow in either direction – what if we hide proposed roads or make them look obnoxious unless they have some additional tags like source and opening_date? Maps typically annotate proposals with “(Expected Completion 2030)” or somesuch. That’s not to say that the date will be an accurate reflection of anything, but it would raise the bar a bit. That said, if there’s a sense that no proposed highway is ever valid, then that’s a different story.

In any case, #215 only deals with roads under construction.

[matkoniecz]

no proposed highway is ever valid

I would be actually in this camp, but I am aware that it is not a consensus position.

But "highway=proposed should be limited to serious proposals, not all official proposals are serious and all highway=proposed should have source in source tag or changeset data" seems matching consensus position

make them look obnoxious unless they have some additional tags like source and opening_date?

Putting source in changeset is at least acceptable

Requiring opening_date is an interesting idea, that I quite like but may be not considered as a standard yet.

[jeisenbe]

In Openstreetmap Carto, the current railway and subway tunnel rendering is similar to the USA map examples for under-construction or proposed roads.

Do you have thoughts about how this would work with subways and other rail tunnels? I understand they are not yet rendered here yet.

Would under-construction railways be eventually rendered?

[1ec5]

Good question. In #101, we were considering rendering railroad tracks with ties rather than an alternating fill, at least for freight and commuter rail. Ties seem to be an uncommon treatment for light rail and subways, but they probably wouldn’t be depicted with an alternating fill in any case. We’re currently rendering tunnels with a faint but solid fill and casing, so it should be possible to combine that with the broken line treatment for tunnels. However, so far in https://github.com/ZeLonewolf/openstreetmap-americana/pull/215#issuecomment-1140313010, I’ve shied away from indicating tunnels or bridges on roads under construction. I had roads in mind, but I suppose the presence of a tunnel would be more notable for a subway under construction.

In the event of a conflict in line treatments, we can also lean on the “(Under Construction)” gloss as seen in #215, since large construction projects tend to be the exception rather than the rule.