Road Types (USA) – comprehensive overhaul of drivable roads

In Detroit I saw a much bigger difference (because Detroit's much bigger and has way more roads to choose from); basically where it used to make me backtrack to get on the nearest freeway entrance, it now sends me along a Principal Arterial (Major Highway) or two for a few miles to get to the next useful freeway entrance downstream. It actually saves a couple minutes.

I think that it is key to reinforce that having a glut of principal arterials classed as MH still helps direct or funnel longer distance routes to a freeway. Even when presented with numerous principal arterials, as long as the freeway truly is the fastest route, Waze will opt for freeway even if it is way out of the way (assuming "fastest route" intended). To one of PhantomSoul's points, I agree that most urban principal arterials are meant for more local use (i.e. non-freeway suburb to suburb or even intra-city) and and not long distance trips, but those are also mixed with US and some major state routes that also have the principal arterial designation and would be more suitable long distance routes. In any case, you still normally get "sucked" onto a freeway as long as your "avoid major highways" option is disabled, but you also have legitimate alternatives at a lower road type if appropriate from the start--not just mid-route as a detour or in the first or last few kilometers.

As an example, entering downtown Detroit from the east side of Ann Arbor/Ypsilanti (about 40 miles), there were only two initial routes suggested pre-NFC: 1) I-94 all the way, and 2) backtracking to get to US-23 to M-14 to I-96 (all freeways). Looking at my routes now from the same location, my primary route is still I-94 (purple in the image), but look at the two alternatives. The green is a bypass off of I-94 using state highway M-39 (previously mH in that stretch, now MH/principal arterial) for about three miles to join I-75. This was not even an option before but it is only three minutes more than the direct I-94 route. The blue alternative is part of the pre-NFC suggested route, but instead of backtracking to take US-23 to M-14 to I-96, Waze now suggests a road straight north to get to M-14 (previously primary street, now mH/minor arterial).

Another consideration is that people should look at how their state DOT actually classifies the roads in your state if you have not. You will find that some states fit the traditional Waze road types well, and others are nowhere close. sketch references the links on each state's mapping resources page, but since those are not altogether complete, here is a link to current FC maps.

Comment: in general, I think FC is a good basis for assigning road type; I think the references to route numbering should be removed. In practice, there is a fairly high degree of correlation between route numbering and road function, but it is definitely not 100%. In those cases where a US highway serves the function of a minor highway because it travels along a narrow street with traffic lights and driveways, or where a state highway serves the function of a major highway because it has few intersections and permits high-speed through travel, the road's function should take precedence over its numbering.

Agreed, but this is an area where different DOTs may treat things differently, so it's worth looking at this in more detail. Some may lower the functional classification of a road such as US-XX through a lower-speed, full-access urban stretch while others (including Michigan) typically do not. We have some state highways at mH and plain city-controlled roads as MH in numerous cases when applying FC. Politics, funding, etc. may come into play with a designation too as sketch mentioned.

I would like to see the rationale documented for the exception for ramps to be used for at-grade connectors.

I believe that dbraughlr may be referencing the bit about jughandles and Michigan lefts specifically. In the case of Michigan Lefts, sketch tested and tweaked the exception for a signed but unnumbered at-grade exit from a roadway. It has to meet specific signage criteria and be at an actual major intersection, not just a standard median crossover. By the way, as GizmoGuy411 and I built that section of the Michigan wiki explaining Michigan Lefts (a colloquial term), we settled on the term "Median U-Turn Intersection" as the best documented naming convention, especially as these are employed under numerous names throughout the US, and they are increasing. If the exception part stays on the revised Road Types page, I believe it should go toward the more or less "official" name for these styles of intersections. Drop "Michigan Left" in favor of MUTI... It should be an at-grade exception in more than a few people's opinions. I think this is mostly because an instruction like "to Telegraph Rd S / US-24 S / to Grand River Ave W / M-16 W" is a bit much to see on a 10-15m segment and pollutes the visual. "Ramps" don't have street names--they carry instructions. The same goes for jughandles and MUTIs.

I believe that primary street should be used for the main road linking two rural towns (and presumably thus the main street through the town) when no higher classification applies (which is often the case). This could well require local knowledge of the editor rather than a published document. Functionally the street is the primary route even though there isn't much traffic.

Perhaps this page does not go into enough detail about how to apply FC in certain circumstances, or perhaps that should be somewhere else, but the guideline as adopted in Michigan when we went FC statewide was to never downgrade a road type just to match functional classification, but it would be okay to maintain or upgrade based on local editor knowledge. Also, we had another one such as what to do with dirt roads, particularly since a number of minor collectors in our state are dirt.

I don't think I can think of any situation where a user might upgrade a road type without approval.

...where a knowledgeable, *trained* user...

I don't envision that champs/RCs will have too hard a time understanding why other champs/RCs have made these determinations. Perhaps oversight via posting all such determinations to a state's Wiki or forum will be sufficient.

That has worked well in the few cases that I have experienced. Documenting any exceptions is extremely important, particularly for CMs who do work outside of their region and would otherwise be unfamiliar with any local considerations. A number of exceptions such as jughandles or the Michigan Left would initially be local ones anyway, so it may be difficult to build a "complete" exception system from the start nationally. Instead, there is likely much quicker testing and potential adoption at the state level, and eventually documentation on the state's wiki page--certainly if a Champ initiates it.

It would be important, however, for Champs to reign in exceptions too (i.e. "Ramps should not be used as at-grade connectors, but please see this list of 75 exceptions...).

Never a downgrade?

"Never" was not a good word because it suggests time. I suppose "never" could be implied in the sense that Waze uses "soon". It could happen someday as population shifts, DOTs change their maps, etc.

The intent, however, is related to any potential decision that an editor has upon finding a road typed higher than the functional classification. If the editor sees a road typed too high versus a FC map, "do not" immediately downgrade the road just to meet the FC map. There could be another rule or exception at work, or it could be local editor judgment from prior to FC being implemented. It's related to the original "at minimum" discussion. To be more clear, this style of language should change if the wiki ends up discussing downgrades.

Here's a recent thread on dirt roads originally for the southwest region that touches on how difficult it is to classify nationally. In largely urban areas, there is usually a paved road within a short distance--even if the dirt road is functionally a minor collector. Out west though, you may not have any other option for miles. With the present system where we cannot separate function from surface, this debate will likely go on without a good compromise at a national level.

Perhaps a note should be added to "street" type to say that it should only be used for paved local roads.

I don't think that would sit well in certain areas based on daknife's comments in that other thread, where perhaps we can shift any discussion of dirt roads. This is a wiki page centered on the function of a road, where there is no good solution when we bring in the surface of a road. Freeway > MH > mH > PS > S > Dirt Road/4x4 Trail is not a good hierarchy. Instead, dirt road could fit into any number of the lower levels whether they be minor or major collector, or even arterial. As dbraughlr stated, not all dirt roads are created equal, but not all regions judge by the same criteria, and even seasonality comes into play in certain places. If we cannot reach a consensus nationally, could there perhaps be an effort to come up with a well-defined list of considerations by region for dirt roads or whatever else, and then national FC guidelines are applied after those regional rules?

Proposal:
Say something like we use the functional class with the exceptions that a road can be upgraded based on local knowledge of function to produce better routing (what happened to the idea that a city wants people to use certain roads and not cut through on residential streets even if they are faster?), or downgraded to dirt where local knowledge is that the road does not really serve its designated function because there is a paved alternative.

I think that this would need to be more explicit since the goal is to avoid as much subjective judgment as possible. "Local knowledge of function" needs to be well-defined as to when it is appropriate versus using FC, and who has the final say in a dispute--the AM? RC?

So in the freeway definition it is stated that there should be "no at-grade intersections." I think that US-50 in this stretch meets the requirement for no at-grade intersections and the exit and entrance roads are not at-grade connectors and are thus properly ramps. However, given the current guidance and the proposed guidance if you interpret these access points "at-grade" then the US-50 would be a major highway and the exits and entrances should not be ramps.

I would state that if you can't cross the highway without either passing over or under the highway then all exits and entrances with acceleration and deceleration lanes along that highway should be considered "grade-separated."

Isn't your US-50 example covered by the at-grade exception for signed, numbered exits--meaning that it already is not truly considered "at-grade" from a wiki standpoint, and the freeway definition of "no at-grade intersections" still holds? Here is a similar configuration where there is no grade separation with I-75, but it is a signed, numbered exit.

It may come under exceptions to the rule, but I would never consider US-40 through Downtown Baltimore to be a Major Highway in any respect. With only 1-2 lanes getting by in some sections, and average speeds less that 20 mph, I would never expect to get routed via US-40 if I was crossing the city. I would consider it a waste of waze's routing engine's time if it considered US-40 as an option (all .05 seconds).

It wouldn't matter if it were a signed US highway or not in this case because Maryland considers it an urban principal arterial (page 208 and following). It would get the "MH" road type regardless. Number of lanes as well as speed (posted, not average) have little to do with function, particularly in an urban area.

Just curious, if you couldn't take a freeway, what option(s) would you choose to get through downtown Baltimore? It looks like US-40 is really the main east-west route through the heart of downtown.

I don't see how your statement "It's not a freeway" is somehow more valid than my statement "It is not a major highway either".

In a discussion weighing functional classification, thankfully Arizona DOT's application of the FHWA guidelines solves the problem for you. That section of US-89 is not a freeway because of access considerations, and it is a principal arterial. No distinction is made at the split where it currently transitions from MH to mH in Waze based on appearance. From a functional standpoint, what benefit is there over the current road type system if we are willing to introduce more subjectivity and complexity for exceptions based on appearance?

Before we implement anything, can we make sure that the links to the functional classification maps for each state are available somewhere besides my Google spreadsheet? The proposed page says that we should check our state's Mapping Resources page, but not all states have one. Would it make more sense to have these links on a centralized page on the wiki rather than spread out on separate state pages--perhaps on the National Resources page? State wiki pages could have a functional classification section and then link to the central page, but it would seem to solve the problem of how to find the maps for the 20+ states without a resource page.