We are a little more piecemeal in the mid-atlantic: Here’s the Maryland discussion.
I did find that one, but thanks for reposting the link. It’s probably true that discussion at this point needs to be local, primarily.
And we’re still working on finding a usable FC map. :roll: The link in the Wiki for HI only works for those who can log into their restricted database. I’ve emailed the DOT to see if they have something for general-public consumption.
It looks like you can access the FC map by first going to the Highways Division GIS Portal Main Menu at http://hwypgis.dot.hawaii.gov/HDOT/index_2nd.htm using Internet Explorer (map would not render in Chrome). Click on “Functional Class” on the menu and install the AdobeSVG plug-in.
Unfortunately, it’s not a user friendly interface and the latest data is from 2006. Although, Virginia’s last official FC update was in 2005. :shock:
I’ll try that, my next shot at IE (I’m on Macs all day long, but we have Windows at home). I hope in vain that my DOT contact would reply to my email, but no such luck so far.
Thanks!
Sketch and I have been discussing the section name for the new table added to this page.
We are debating a few name options and wanted to get some additional feedback. Options we have discussed for that section include:
- Quick reference chart
- Cross reference table
- Road type correlation chart
- Correlation chart
- FC cross reference
- Functional class cross reference
I will say that “quick reference chart” was the name I originally used on the page. The idea is similar to that of the glossy page you get with a new TV, for example — duplicative of information already in the full guide, but in an easy-to-digest format.
There seems to be a little confusion about how Freeways are supposed to interface with the rest of the driveable network. I read the wiki notes below to mean that a Freeway segment may only connect to 1) another freeway segment, 2) a ramp segment:
Is this an incorrect assumption? If so, can the Wiki be updated to clarify that it is acceptable for the segments used for entrance and exit ramps to be something other than “ramp” type?
If this is a correct assumption, can we add a note that the entrance and exit ramp segments need to actually be “ramp” types for all Freeways?
Thanks!
Have you got an example of this where the Fwy/Expy isn’t ending and no longer limited access?
Not sure if this is the sort of example you’re looking for, but Interstate 27 in Texas starts on surface streets in Lubbock and ends on surface streets in Amarillo. No ramps involved.
I have certainly seen cases where freeways change between MH or mH without a ramp.
I guess the $10 question now is: should we allow Freeway segments to connect directly to other segments that are not Freeway or Ramp? Either way, I think the wiki should be touched up to provide clarity. As it reads now, I am inclined to believe that a Freeway should only connect to another Freeway, or a Ramp. Never to a MH, dirt road, street, etc. If you want to connect to one of those, use a ramp.
If you are allowed to connect directly to freeways, then I think the definition needs to be re-worked to allow that, since connecting it directly to a street or dirt road segment would not provide for “only connecting via interchanges”
Why would you use a ramp if a major highway becomes a freeway using the same road surface?
https://www.waze.com/editor/?zoom=5&lat=33.51935&lon=-101.84326&layers=943&segments=50324644&env=usa
US-87 becomes I-27 and vice versa. Or are you saying the connecting points between the two should be ramps? How long would the ramps be?
A freeway can certainly end or begin at another type road, and many do. I thought of adding that a few days ago, but I wasn’t near a computer.
As for mid-freeway connections to major/minor highways, this is possible as well, especially at the beginning/end of a concurrency (say, when US-11 and I-59 run together for a time). This will be covered by this section of the Interchanges JSG, which is pending a rewrite. That’s still a type of interchange, though. Interchanges may use non-ramp segments if they are freeway/highway splits, mostly to achieve visual continuity on the map, but the point is that it’s an interchange and not an intersection.
If there’s another type of junction you’re concerned with, I’d like to know.
I think the point is we just need to add wording to support some of these other conditions that are missing from the Wiki.
Sketch, do you want to take a first shot at it? Or let me know and I am happy to modify that section to describe these other conditions.
This is what I was getting at with my early comment. Interstate/Fwy/Expy all have common occurrences of terminating into another road type, and it’s usually the next step down in NFC.
When a concurrency diverges I’m not sure we can really get away with not using ramps simply because there’s usually a need for pathfinders, at least until we get that new feature.
Shouldn’t the cross reference chart be near the top of the page?
I suggest that the entire section “FC cross reference” be appended to the first section “Functional classification”
I have some thoughts that may be random and naive, but wanted to share them here for comment so I can learn more about this issue. I have some observations, conclusion, and suggestion.
Nnote has taken some detailed research regarding AZ FC and tried to apply it to the state. Being his neighbor, we said NM would try to collaborate on roads crossing state lines. I am in a dialoge with Nnote, and my mentee 
irowiki who is based in the Farmington NM about how we should do this.
What conclude (for now) by looking in AZ to see what they did I see two things I will try to describe more in a bit:
(1) Phoenix, a rather large city, is comprised of a bunch of Minor Highways and Major Highways. This seems odd at first. It seems biased toward having Major Highways every half mile or every mile or so. Take a look. It seems highly differentiated.
(2) Rural areas of AZ currently seem biased to be less highways and more primary streets and streets. So the major arterial between distant cities can be primary streets. It seems under-differentiated.
So, does this make sense?
I can see some logic for (1) in that if you truly want to provide differentiation in a highly populated urban area, you need to bring in more use of MH and mH to augment all the streets and primary streets with different levels of traffic and usage. If you don’t do this you under-differentiate for the amount of road use.
It seems that (2) is a problem for me. It seems that it is applying the same rules (1) in a city like Phoenix to the rural areas. In that case, fewer cars go over a major road between cities than go down a neighborhood street in Phoenix. If you use that as the benchmark, then you mark everything as a street. That leads to under-differentiation in the rural area. I think from all I have learned as an editor that you need to at least have mH connecting cities.
So that was the observation and a conclusion about the AZ work so far, which, like all of us is struggling with how to apply a new FC in different ways. I think that what we don’t want to do is look at every state’s FC and apply it absolutely. We are working at least a national problem here about how Waze algorithms route users. It’s not about how the various state’s view the world. That’s why we have a Wiki FC guide. Even with that though, there could be issues.
Given the observations (1) and (2) above, it seems to me that what is needed is a sliding scale of FC that provides optimum dynamic range (sorry, the engineer in me coming out) that slides between urban areas and rural areas. Our “dynamic range” is F/Ramp-MH-mH-PS-S-Dirt. That is a dynamic range of six (6) levels. If we apply that across all roads absolutely then we don’t have enough dynamic range to cover both urban and rural areas. If we interpret FC slightly differently between urban areas (like AZ is doing for Phoenix now) and rural areas (like having MH and mH betwen cities all the time), then we create a much wider dynamic range for the whole country, probably on the order of a synthetic range of nine (9) or ten (10) levels. Of course this needs some flexibility to allow the transition and special cases.
I have always argued that very rural dirt roads can be street, primary street, or minor highway. This is an example of the rural interpretation of FC that allows better dynamic range in a rural setting rather than just typing everything to be dirt or street.
Hope that makes sense.
There used to be separate Urban/Ural FC guidelines until 2010(?) and the last directives were supposed to unify the two, however some states have either not completed that work or have yet to publish it to publicly accessible locations. If you’ve got FC maps that have Urban/Ural legends, it’s the old system and judgment must be applied.
As far as inter-city connectivity goes, US/SR minimum typing tends to resolve that in most cases. Fixing failures of reasonable expected routes will be a judgement call based on local knowledge and “how would I get there looking at this paper map” 
. Until we get in-editor annotations, exceptions are going to be an issue that can only be protected by higher locks and documenting in the state’s wiki.
The GIS map we are using for FC in AZ is from ADOT itself. We were provided with it after contacting ADOT and were very fortunate they provided it to us. While at first we were very sceptical about the states FC, we studied and debated it a lot before implementing it (we also had a variety of not such nice thoughts about the map and the persons responsible for it). As we studied it we found it to be very good and especially as we implemented it we found it to be actually very logical. It took a few to get used to something new… but me personally I see the sense in what it is. As far as rural and urban areas go, another AZ editor did a complete study an write up on this for us, Fredo-p will post his details on this in the thread soon.