Talk:Utah/highway classification

How the page is organized

Currently the page is organized by highway network (i.e., interstates, US Route, Utah Routes). I feel like it would be better to organize it by OSM classification (motorway, trunk, primary, secondary). Also I'm not a fan of enumerating every single route here. That's what the map itself is for. Would it be alright if we pared it down? Aweech (talk) 16:04, 8 January 2022 (UTC)

Yeah for sure, that makes a lot of sense. I don't anticipate having any significant free time this weekend, but I can do the reorganization next week. I'll probably keep all the old text in the page source for reference (commenting it out from appearing on the page itself), but you're right that it doesn't need to be displayed. I can try to organize it by continuous corridors too (e.g. US 191/491 from I-70 to CO) instead of by route (e.g. all of US 191, which doesn't make much sense as a through route). Oregonian3 (talk) 16:13, 8 January 2022 (UTC)

User:Aweech I made some modifications to the page to list all the proposed trunk routes. I'll do the primary routes when I have the chance as well. Let me know what you think. Oregonian3 (talk) 15:23, 10 January 2022 (UTC)

UT 20/US 89

I disagree with Flagstaff not being a large-enough city to be a trunk destination, as it has a population of ~78k as of 2021. Even if it wasn't large enough, there are still around 6 million other people in the Phoenix and Tucson metros who would likely use the UT 20/US 89 route if they traveled to Northern Utah. Both OSRM and GraphHopper consider the US 89 corridor to be the best route between SLC and Phoenix/Tucson. It even serves traffic coming from as far south as Mexico to as far north as Eastern Idaho and Western Montana. However I agree with UT 179 not being trunk. It should either be motorway because it is a direct spur off I-80 with no at-grade intersections (and motorway spurs/stubs are not problematic because it's a structure-based class) or primary because it connects to another primary road. Joseph (T • C) 23:28, 10 January 2022‎

That's certainly a fair argument. Does anyone else have thoughts? FWIW, Google Maps, depending on the traffic conditions, directs me over either I-15/US 93, or US 89/I-17 to get from Salt Lake to Phoenix. Oregonian3 (talk) 01:02, 11 January 2022 (UTC)

FYI, your signature seems to be broken for some reason. I had to close some HTML tags and links. Oregonian3 (talk) 01:04, 11 January 2022 (UTC)

To be fair, Google Maps does not have the best navigation system. It usually routes along whichever route looks the fastest. I've had many instances where I could add a destination along a road that looks like a shortcut and sure enough the travel time is shorter. Also not sure what keeps happening to my signature so I'm going to change it. It works fine on Wikipedia but I guess not here. Joseph (T • C) 01:18, 11 January 2022 (UTC)

You know what...thinking about it more I'm thinking that I could live with this road being a trunk route. It's clearly more important as a through route than the surrounding primary roads, especially if roads like UT 12 are also upgraded to primary (which I will propose on this page when I update it). Oregonian3 (talk) 14:43, 12 January 2022 (UTC)

US 6

What people say the classification of US 6 from I-15 to UT 132 should be keeps varying between secondary and trunk. I've got to say that this section should be a very neutral primary, because, while it has much less traffic than UT 132 in its southern section, it's higher than UT 132 at its peak traffic volumes in the northeast. But I should say that highway classification should 75% rely on what it connects since it's more useful for people that use OSM as a navigation system. If we went solely or primarily based off traffic volumes then most rural highways would be tertiary and most city streets would be trunk. Going off connectivity and travel time, US 6 is the fastest route between Delta and Tooele and Delta and Santaquin, which I would consider, at the bare minimum, primary destinations. US 6 and I-15 to SLC from Delta also have nearly the same exact travel time, with US 6 being a couple minutes down to just seconds longer than if someone went I-15 via UT 132. It's also the only road that goes to Eureka, which I'd also probably consider a primary destination too. Primary in general is a more flexible tag than others like trunk and motorway since it can be applied to generally any road that is regionally important. Joseph (T • C) 01:45, 11 January 2022 (UTC)

And honestly, tagging a U.S. Route lower than primary would defeat the purpose of a lot of OSM's provided highway tags. Primary is supposed to be for the minor U.S. Routes and trunk for the major ones. Secondary is usually for the lowest-tier business routes. You also mentioned in a changeset comment that there are multiple secondary U.S. Routes, however I can't find any, especially since I watched the final few be upgraded to primary over last year during all the trunk roads being upgraded. Last one I came across was U.S. 95 in Arizona tagged as secondary because it briefly overlapped with a business route (however I upgraded it to trunk to finish the Canamex route). Joseph (T • C) 01:53, 11 January 2022 (UTC)

I'll respond to this point by point.

• Multiple secondary (or even tertiary) US routes. Here are just a few examples: US 40 west of Denver where it parallels I-70, US 30 west of The Dalles Oregon where it parallels I-84, US 191 between Price and Duchesne in Utah until I recently upgraded it. I think we can both agree (or at least I'd certainly hope, because I'd call into question the competence of anyone who disagrees) that tagging those interstate-paralleling roads as primary would be utterly nonsensical; they serve nothing apart from a few houses, with zero use otherwise. Admittedly those are more extreme examples than this section of US 6 because they directly parallel an interstate, but your point about there being no secondary US routes is incorrect.
• Tagging a US route as secondary is actually exactly the purpose of these guidelines. If we wanted all US routes to be primary, we'd just use a classification system like Europe where the designation of the road has a one-to-one correspondence with the OSM class. But we don't, because such a system would be nonsensical in the US. US routes vary greatly in importance and quality. To quote the new guideline from here, primary roads "This may include US highways, business loops on the interstate network, higher-importance state roads, and roads which provide connectivity to minor population centers". This explicitly states that primary routes may include US routes, it does not say that they must include US routes. The argument that a route must be primary because it is a US route holds no water, and defeats the entire purpose of the US road classification guidelines.
• With regards to the merits of tagging this section of US 6 as primary, consider the following: the nearby primary routes all serve as access to mid-importance population centers (e.g. UT 132, UT 28, US 89) or serve as part of an important route that traverses the state (e.g. US 6 west of Delta, US 50). This section of US 6, in contrast, serves the tiny town of Eureka. Eureka has less than 1000 residents, and couldn't even really be called a minor population center. In short, this section of US 6 meets the definition of a local road, rather than as any sort of regional access road to population centers.
• Obviously a rural road is going to have lower traffic counts than an urban road. It would be comparing apples to oranges. A rural road with 5000 cars per day is almost certainly going to be trunk in this area of the US, while an urban road with 5000 cars per day is probably tertiary or residential in most cases. But we can compare the traffic counts of roads in similar areas to each other. For example, it is a valid comparison to compare the traffic counts of UT 132 with those of US 6, as they are similarly-designed rural roads. Likewise, it is valid to compare two adjacent city streets to each other. Traffic counts should certainly not be the only metric used in determining classification, but it is one easily-quantifiable metric that can be useful, along with others, in assessing how important a road is. As to peak traffic volumes, that is a terrible metric. An upper bound on the through traffic using a route is the lowest traffic count on the section of road. The peak traffic count is useful to show how many people use the road for local access, but the lowest traffic count is the one that is useful to show how many people use the route as a through route. Therefore, the lowest traffic count is the one that should be considered when considering importance to the road network overall. Most people who exit I-15 at Exit 244 are just heading into Santaquin rather than following US 6 the entire way.
• With regards to the Delta/Tooele or Tooele/Santaquin connections, the US classification guideline says nothing about this. All it states is that "roads which provide connectivity to minor population centers" should be primary. I take this to mean that every mid-sized town (i.e. a minor population center) should be served by a primary or higher road in some way. In the case of Tooele, it's served by the primary UT 36 from the north. In the case of Santaquin, it's served by the motorway I-15. In the case of Delta, it's served by the primary US 50 and US 6/UT 132 corridors. The section of US 6 that's currently secondary only serves to connect these areas to each other, not to the rest of the road network, which I do not believe means that it must be primary; the road network connecting these three large towns to the major population centers of the area (Provo, SLC, etc) is already primary.
• To wrap up, I view trunk/primary/secondary/tertiary as a hierarchy of road importance. Trunk roads are the most important, followed by primary, followed by secondary, followed by tertiary. This is completely independent of how the road is designated (e.g. as a US route, state route, or locally-maintained road). On the balance of factors that play into road importance (connectivity, traffic counts, destinations served, road quality), this section of US 6 falls squarely within the range of secondary. Probably on the higher end of secondary, but secondary nonetheless. Oregonian3 (talk) 15:55, 11 January 2022 (UTC)

You've got fair points, some I agree with and some I disagree with. I think that the west right now is just one of the more controversial areas to work in right now. Between you, me, another northern Nevada user, and the users in the local Utah channel, there are a lot of changes that are being made around Utah that don't correspond with each other, so if we could all discuss with each other in one place and meet middle ground I think we can form a plan and work together. In at least the US, winter is OSM's most important season as its data will be needed for the users of apps with OSM data who are travelling out to warmer places like the west and south for the winter to go on vacation and camping, hiking, biking, etc. Getting things right in this region is crucial for getting people around. Joseph (T • C) 20:01, 11 January 2022 (UTC)

Referencing the definitions, and population areas

Thanks for getting this going for UT. I don't have a lot of specific feedback on the roads themselves, but for the wiki page, I have a few suggestions.

First, it would be good to directly reference the motorway and trunk definitions in the 2021 Highway Guidance (even if that is just linking to them, rather than restating them). It is important that we are using the same definitions when assessing the roads, particularly trunk vs primary, as inconsistent definitions in the past is part of how we ended up in this mess. There will always be an element of subjectivity, but as long as we are talking from the same sheet then it is easier to hash those out rather than talk past one another.

Second, listing out some of the major transportation areas or population centers around UT would be helpful. What regions are the roads linking? This helps because it sets context - a road with 10,000 a day in the middle of SLC could be a secondary road, but a road with 2,000 a day might still be trunk in a very rural area if it is the most important route serving that area. I think this is particularly important for these western rural states that have one huge population center and then tons of small communities. An importance based trunk definition helps keep rural areas from getting under-classified when their roads are compared to densely populated areas.

Third, I've found a list of resources to be helpful when looking at other states, some of the state-specific guidance docs have added them, and I find it helpful to quickly pull up things like traffic counts, or NHA maps for the state, or the state's own classification, etc. I'll add some as I come across them, but I don't have a lot of bookmarks for UT. --Phidauex (talk) 20:35, 11 January 2022 (UTC)

Yeah, definitely an importance-based definition is the best. Unfortunately, importance is an un-measurable quantity, meaning that we have to resort to proxies for it. Regions the roads link together, traffic counts, quality of the road...those are some of the more measurable features that we can use as a proxy for importance. Deciding what measurable features go into the importance definition, and where the trunk/primary/secondary/tertiary cutoffs are, is important. And good call on the resources, good to have. I do think that functional class and NHS status are pretty useless.... I know in the past that there's been consensus not to rely on those since they're often so far out of touch with reality.

The burning question is where the trunk/primary/secondary/tertiary cutoffs are within importance. I'm completely disregarding urban roads for now: a fully separate classification scheme is needed for them, and that can come later I think. For rural roads, I believe that a good classification scheme should have all four of these classifications used, with there being more secondary than primary roads, and more primary than trunk roads. Any scheme that only has, for instance, a few secondary roads when encompassing all state highways is a bad scheme: having most highways as primary tells the reader nothing about their relative importances. I will update the wiki page as soon as I can with a full list of proposed primary rural roads as well. Oregonian3 (talk) 14:40, 12 January 2022 (UTC)

That all makes sense. I think the thing I like looking at state and US classifications for is as a tie-breaker. I see importance as gathering up as many check boxes as a road can get, when compared to another road. Higher traffic? Direct route? Heavier construction? Fewer seasonal closures? Higher state classification? Etc. So while I think it would be wrong to map OSM classifications directly to state or federal classifications, I think those classifications still tell us something important about road maintenance and freight priorities, and should be included as one of many considerations. There are certainly situations where the state classification is way off, or very old, so I never follow it blindly.

As for quantity of trunk/primary/secondary roads, I agree with your thinking, but I also think that with an importance based definition that includes "what purpose is the road serving", not just "how does the road compare to other roads", you might end up with unique situations, like two population areas connected by a single road. That road might now be trunk, even though it is the only road in the area, because it serves the purpose of connecting population centers. I think this is my issue with US 550 in CO - it links important population centers, even though it isn't much of a road by construction. --Phidauex (talk) 18:03, 12 January 2022 (UTC)

I've also added a list of all the rural UT roads that I think should be primary on the wiki page. Oregonian3 (talk) 16:21, 13 January 2022 (UTC)

UT trunk classification on map now matches this wiki page

I made the few remaining changes this morning (US 50, UT 224, and UT 179), and the now the actual classification of trunk roads on the map matches what is on this page. Oregonian3 (talk) 15:13, 15 January 2022 (UTC)

UT 266 and UT 152

UT 266 and UT 152 should probably also be downgraded to primary with expressway=yes since they are only intra-metro expressways and don't really serve any long-distance traffic. Joseph (T • C) 01:07, 25 January 2022 (UTC)

To quote the trunk guidelines trunk roads in cities are "expressways that meet most, but not all, of the requirements for highway=motorway, and provide connectivity between motorways and other trunk roads".

So that begs the question: do these two roads meet most but not all of the requirements for motorways? Both do have divided carriageways and significantly fewer intersections than a typical city street, and are designed for high-speed travel from one end to the other. However, they have no on- or off-ramps and several traffic signals. Thus, they meet around half the criteria to be considered motorways. Is this enough for them to be trunk? Oregonian3 (talk) 22:06, 25 January 2022 (UTC)

The Wiki's guidelines are rather dated since trunk is now importance-based, making motorway the only structure-based tag. Any expressway should be tagged based on how important it is (tertiary through trunk) with the key expressway=yes. The only remaining reasons to tag an expressway trunk (beside the ones that connect important population centers) are if it is sandwiched between or connecting two motorways or motorway segments (examples: [1] [2]) or links to a major airport (examples: [3] [4]). I might also include ring roads for major cities in there too.

These highways seem to just be expressway arterials that help with rush hour traffic and general commutes, so I'd say no, these do not meet the requirements for trunk, at least not anymore. Joseph (T • C) 04:59, 26 January 2022 (UTC)

Primary roads in urban areas

The way I see it, there are a few distinct urban areas in Utah that are possibly big enough to have primary roads aside from the roads that provide access to them. I think we can split this up into a few areas that are naturally split by geogrpahic features. From north to south, these are Logan, Ogden, Bountiful, the Salt Lake Valley, the Utah Valley, Cedar City, and the St. George area. I think the current set of primary roads in these areas is generally pretty accurate in reflecting which are the most important roads, but there's probably some small tweaks that could be made. Oregonian3 (talk) 21:56, 13 February 2022 (UTC)

Salt Lake Valley

I'm most familiar with the Salt Lake Valley out of any of these areas, so perhaps it's a good idea to start there. Here's a list of roads that are currently primary, and a list of possible upgrade candidates.

Obvious primary roads that I can't see how anyone would debate:

• South Temple from State Street to 700 E
• Foothill Drive/500 S/400 S from I-15 to I-80/215
• 500 S/600 S from I-80 to 700 E
• 3500 S/3300 S from Mountain View Corridor to I-215 (east)
• 4700 S/4500 S from Bangerter Highway to 700 E
• 5400 S/5300 S from Mountain View Corridor to State Street
• 9000 S/9400 S from Mountain View Corridor to Highland Drive
• South Jordan Parkway/10600 S from Mountain View Corridor to 1300 E
• Daybreak Parkway/11400 S from Mountain View Corridor to State Street
• 12600 S/12300 S from Mountain View Corridor to 1300 E
• 13400 S from Mountain View Corridor to Bangerter Highway
• 5600 W from Mountain View Corridor to I-80
• Redwood Road from Utah County line to I-80
• State Street from 10600 S to North Temple
• 700 E/900 E from 10600 S to South Temple
• 1300 E/Union Park Avenue from 12300 S to I-215
• Highland Drive/Van Winkle from 9400 S to 700 E

Decisions that need to be made:

• Northern downtown SLC: Which route should be the primary route into downtown from the north, connecting to the State Street/North Temple intersection? There are three routes that have relatively equal traffic: 600 N -> 300 W -> North Temple, Beck Street -> 300 W -> North Temple, and Beck St -> Victory Road -> Columbus St -> 300 N -> State St. Currently the 600 N alignment is primary while the other two are secondary. I think this is the best way for it to be: it's the highest-quality road out of all of them and stays on the interstate the longest. I could also see the argument for the Victory Road alignment to be primary: it's actually the fastest route to eastern downtown, the Avenues, and the U of U. However, it's a narrow lower-quality road with an unintuitive routing.
• Sugar House roads: 2100 S and 1300 E. 2100 S between 700 E and 1300 E is a major road through the heart of Sugar House, with very high traffic. However, it's closely-paralleled by I-80. 1300 E between 500 S and I-80 is a very busy route to many destinations, including the U, Sugar House, Westminster College, and more. However, it's a two-lane road north of 2100 S, limiting its usefulness. I could see the arguments for either primary or secondary for both of these roads.
• Magna roads: Should any of 3500 S, 7200 W, or 8400 W be primary through Magna? I'm not familiar with this area, but from traffic count data and looking at aerial imagery I'd think it would be best to have 7200 W north of 3500 S and 3500 S east of 7200 W primary, with the other portions secondary.
• Herriman roads: I'm entirely unfamiliar with this area, and traffic count data doesn't really help considering it's exploded so much these past few years. Are there any roads west of Mountain View that should be primary? I'll defer to anyone familiar with this area here.
• 4100 S/3900 S, 6200 S, and. 7800 S: Major roads running across the valley with high traffic counts, with many similarities to 3300 S, 4500 S, and 5400 S. However, unlike those three, these roads do not have direct interchanges with any of the interstates, and generally have slightly less traffic. They're borderline cases; I could see arguments for either.
• 6200 S: A similar case to 3900 S, but only runs across the western half of the valley.
• 7000 S/7200 S/Fort Union Blvd: Also similar to the above roads, but this one does have an interchange with I-15. However, it's closely-paralleled by I-215, limiting its utility as a through route.
• 5600 W: This road used to be a clear primary, until the Mountain View Corridor was built closely paralleling it. Now it's in a more similar situation to roads like 2100 S or 7200 S, where it's a major road but doesn't really serve much through traffic.
• 1300 E from Van Winkle to Union Park: right on the border between primary and secondary, I'd say. An important route from the southern valley to Millcreek, Murray, and Holladay. But it's slightly less important than the surrounding primary roads, and has no interchange with I-215.
• 2300 E: This is the most important north/south route through Millcreek and Holladay, in an area that currently has no primary north/south roads. However, like 1300 E through Sugar House, it's a two-lane road that's not well-suited to high traffic volumes.
• 6200 S/Wasatch Blvd: Similar to 1300 E, this is a very major and important north/south route that is wholly inadequate for the amount of traffic it gets (not that I'm for road expansion, in fact I'm quite against it in the vast majority of circumstances). There's also the problem of where to extend it to on the southern end: there's no logical primary continuation of the road beyond the Little Cottonwood Road intersection.

I think that pretty much covers all the roads in the Salt Lake Valley that could reasonably be considered primary. Any thoughts? Oregonian3 (talk) 21:56, 13 February 2022 (UTC)

Road classification guidelines

Now that we seem to have a stable list of rural trunk and primary roads given that nobody's proposed any changes in half a year, I think we need to create some criteria to determine what qualifies a road as trunk or primary. This will give some guidance both to why the trunk and primary roads were chosen, and how to classify secondary/tertiary/unclassified/track/residential roads. Here's my draft that I would propose.

Trunk

• Serve as the best (but not necessarily the shortest) route connecting metropolitan statistical areas to each other or to micropolitan statistical areas.
• Often have frequent passing lanes and high speed limits.
• Should not have frequent sharp curves or other similar roadway deficiencies.
• Have high traffic counts, at least several thousand vehicles per day.

Primary

• Connect micropolitan statistical areas to each other, or serve as access roads to medium-sized towns that are not part of an MSA.
• Should have good pavement quality, but may have frequent sharp curves or other deficiencies.
• Must be open year-round.
• Have at least several hundred vehicles per day.
• Will usually be state-maintained, although this is not a requirement.

Secondary

• All incorporated towns should be served by a secondary or higher road.
• The best routes between all towns should be at least secondary.
• Must be paved.
• Can serve as local access to major recreation destinations (e.g. national parks, ski resorts).

Tertiary

• Can be unpaved, but should be drivable in any low-clearance 2WD passenger car.
• Can act as routes serving unincorporated communities or recreation destinations.
• Can be poor-quality but drivable mountain passes or desert roads or the like, or the most popular national forest roads.

Unclassified

• Should be drivable by a mid-clearance 4WD vehicle.
• Does not primarily serve residences as its main function.

Residential

• Roads that serve primarily residences within communities.

Track

• Any road that is only drivable using a high-clearance vehicle.
• Some old roads that have been converted to hiking trails can be tagged as track roads.

Any thoughts? Oregonian3 (talk) 20:16, 26 July 2022 (UTC)