> The concept of expressway and freeway are reasonably well known concepts; > it makes a lot of sense to map trunk and motorway to those concepts.
I agree with freeways but not with expressways. I have no data to back this claim up, but I'm fairly convinced that, while the average citizen could easily differentiate between "freeway" and "not freeway", they would be hard pressed to do the same with an expressway. Anecdotal, but even when I spent time in the Santa Clara area which has a robust expressway system, I never heard a single person say "and then get on the expressway...", or even the word 'expressway' mentioned outside of it being the suffix of a road name. You're right that it's not a terribly difficult concept to understand and thus map, but I disagree that it's an important concept in explaining the road hierarchy in the US, so much so that we can equate an entire class of importance with them. We have a robust, clearly signposted freeway network in the US. We do not have the same with expressways. Roads tend to go in and out of "expressway" qualification depending on context, traffic levels of connecting roads, and highway budget & design policy. A road being built as an expressway is suggestive of its importance at best, and certainly not indicative. Edmonton has many roads around the east and west of the downtown area that are clearly built as expressways. However, they are only tagged secondary because, fundamentally, you only really need to use them to get around the immediate vicinity. Despite being very high quality roads, they aren't all that important in the grand scheme. I can point to many examples of urban roads that likely meet an expressway definition in my current home city of Reno, including one under construction. It would be absurd to me to tag them as being second in importance only to motorways just because they are well-built roads, because they're unimportant outside of getting around the relatively small Reno-Sparks metropolitan area. The "highway" key is about importance. The only category we have full-stop made equivalent with a type of road design is "motorway". From trunk on down, it is just different grades of importance. These are how the definitions are listed on the 'Key:highway' page, which I consider to be definitive. The fact that the words "trunk", "primary", "secondary", ... are used is an artifact of the UK roots of OSM. Had this project started in the US, the keys would probably be "freeway", "principal_artery", "major_artery", "minor_artery", "major_collector", ... leaving UK users scratching their heads trying to figure out how to adapt these definitions to their own network. In countries with signposted expressway systems, it is meaningful in understanding the road network to equate trunk with expressway, so they do that. I don't think doing the same is meaningful in the U.S. given how much variability and inconsistency there is with how and where expressways are constructed. > Even a lot of renderers make this same assumption: mkgmap maps trunk to > Garmin's concept of expressway and motorway to freeway. Osmand, easily the > most popular data consumer for OpenStreetMap, makes the same assumption (to > the point that most of it's map painting styles, the only differentiation > between trunk and motorway is a color pallette shift). It really wouldn't > hurt the US community to have a "come to Jesus" moment on this, > particularly when using the MUTCD definitions for expressway and freeway as > qualifiers for trunk and freeway, makes this relatively easy. The > corollary to "don't tag for the renderer" is "don't break the renderer". > Highways without access control being excluded from trunk or motorway isn't > an intrinsically bad assumption to make. Especially if we come to > agreement on that, we can start having a productive talk on how to make > carto not suck for Americans without breaking it for everyone else. I'm really not that concerned with how third-party applications decide to paint their roads. It's up to them to work with the data we provide, not the other way around. If it is important to Garmin or other applications to translate expressways, this can usually be deduced from other tags, or we can trivially add an "expressway=" tag. I also disagree that the carto in the US is bad, other than our insistence that two-lane are categorically not trunk leaving meaningless splatters of orange around the map at low zoom. Also, apologies ahead of time if I keep breaking the archive hierarchy, I'm not totally familiar with how to drive a mailing list and I have yet to find a guide online that explains how. _______________________________________________ Talk-us mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-us
