Functional classification is a system by which roads are classified using a set of criteria selected by the Federal Highway Administration (FHWA). These criteria include not only the physical attributes of the road but also efficiency of travel, number of access points, speed limits, route spacing, actual usage, and continuity. This can lead to quite different classifications for roads that appear similar. For example, a six-lane divided road in an urbanized area may be a Collector (Primary Street); a two-lane road through the middle of a town may be a principal arterial (Major Highway).
In Waze, functional classification is used to determine road type in the United States.
Functional classification is a national standard, but functional classification maps are published by state departments of transportation.
Experimentation over the past 6 months has shown that using these functional classification road typing schemes VASTLY improves Waze routing. It is now being implemented nationwide.
Below is a table that shows how to use the Waze road types to match the MDOT maps.
In addition to setting the road type, care should be taken that these roads have been carefully examined for continuity. Go along each road and be sure that any connecting roads have proper turn permissions set, and that there are no gaps in coverage. Mississippi State Highways should be named in the MS-## format. U.S. Highways should be named in the US-## format. Divided highways should have the cardinal direction, and crossings (u-turns). At-grade connectors should be typed properly (the lesser of two types that it connects to). Uturns should be of Street type except in the case of “Michigan left” type uturns.
Only then should any area be marked “Complete”. (list in next post)
Contact me or Sketch through PM to get the status of any area changed to “Complete”.
Items in Bold Green are complete. Items in Blue are currently being worked on with the name of the user working on it in parentheses. Please contact jasonh300 or Sketch via PM to update this list.
Urban areas Biloxi-Gulfport
Hattiesburg Jackson (bart99gt) Memphis Pascagoula
Small-Urban Areas Aberdeen Amory Batesville Booneville
Brookhaven Carthage Clarksdale Cleveland
Columbia
Columbus Corinth
Crystal-Springs Forest Greenville
Greenwood Grenada
Hernando Holly-Springs
Indianola
Kosciusko
Laurel
Leland
Louisville
McComb Meridian bart99gt Natchez
New-Albany Oxford (coldillusions)
Philadelphia Picayune
Pontotoc City
Ripley
Senatobia
Starkville Tupelo (coldillusions) Vicksburg
Waynesboro West Point Winona
Yazoo City
County list
Adams County Alcorn County
Amite County
Attala County Benton County Bolivar County
Calhoun County Carroll County (CrackedLCD)
Chickasaw County
Choctaw County
Claiborne County
Clarke County Clay County
Coahoma County Copiah County (majorjc_MS)
Covington County DeSoto County
Forrest County
Franklin County
George County
Greene County Grenada County Hancock County (jasonh300) Harrison County (jasonh300)
Hinds County
Holmes County
Humphreys County Issaquena County
Itawamba County Jackson County
Jasper County
Jefferson County
Jefferson Davis County Jones County
Kemper County
Lafayette County
Lamar County
Lauderdale County
Lawrence County
Leake County Lee County (coldillusions) Leflore County (CrackedLCD)
Lincoln County
Lowndes County
Madison County
Marion County Marshall County
Monroe County
Montgomery County Neshoba County
Newton County
Noxubee County
Oktibbeha County Panola County Pearl River County Perry County
Pike County
Pontotoc County Prentiss County
Quitman County Rankin County (majorjc_MS) Scott County (majorjc_MS) Sharkey County Simpson County (majorjc_MS) Smith County (majorjc_MS)
Stone County
Sunflower County
Tallahatchie County Tate County
Tippah County Tishomingo County Tunica County
Union County
Walthall County Warren County Washington County
Wayne County
Webster County
Wilkinson County Winston County Yalobusha County (CrackedLCD)
Yazoo County
For those of you working on the Functional Classification Project, please take a look at this post for some tips, based on a lot of the problems I’m finding in both edited and unedited areas. This is not directly related to functional classification, but it’s good info for general cleanup.
US and state highway systems also play a part in road type. Functional class and highway system each determine the minimum type a road should be. This chart, along with the text of the article it’s in, should help you to understand how it works, but keep in mind that Mississippi’s handling of rural major collectors is different than some states’. (Also, I don’t think Mississippi’s usage of county roads really justifies setting them all to at least PS.)
Sorry for any confusion, and sorry if you have to go back and re-edit certain areas now. I can offer a hand in that. Let me know if you have any questions. I can create a Mississippi-specific version of that chart if you think it would be helpful.
This is about a mile from my house, and happens to be right on the border between the Memphis urban area map and the DeSoto County rural classification map.
Pleasant Hill Rd on the urban map is classified as a minor arterial route, but on the county map, it is a major collector. So now, to stay consistent with the urban classification, I should upgrade it to a minor highway as well? IMHO, this one probably should be a mH all the way to I-55 anyway as it more or less is an arterial route through that part of the county.
Wheeler Rd never enters an urban area, and is designated as a Major collector, and I’ve had it marked as a primary street. Now, according to the chart this should be a minor highway? Or should it just depend on what we judge the importance of the street to be and classify them as mH/PS as appropriate?
Hmm – OK. I was just keeping the rule as Jason had written it, but I think it’s a better idea to default to the lower of the two types, unless the road becomes the higher of the two as it enters an urban area.
I made an edit to one of the footnotes on the FC chart to clear things up a bit. I’ve seen a few sections of road that were improperly classified and I think it may be due to some confusion about how to interpret the chart.
Basically, as per the discussion above, if there is more than one choice in the chart, default to the LOWER of the two.
My personal preference is to carry the urban classification (if it is higher than the surrounding rural one) out far enough to provide a transition from the urban to rural environment (if someone needs examples, just ask), and to keep a road from changing classification(s) back and forth because it skips in and out of an urban area.
Remember, the chart is a MINIMUM classification. If you feel, that in your judgement, that a road should be classified higher, then do so. These maps only get updated every few years, so roads may have been widened, reconfigured, etc…
This seems more or less consistent with what I meant. The point is that a road shouldn’t drop down in type between two urban areas, it should remain consistent through its rural stretch.
So if a road is Minor Hwy in one urban area, then goes thru rural where it could be Minor Hwy or PS, then gets to another urban area where it’s Minor Hwy, then Minor Hwy should be chosen. In other words, this is the situation that overcomes the default lower choice.
Otherwise, the lower of the two is fine, for example if the road is PS in one urban area, PS or Minor between, and Minor in the next urban area, then PS is fine.
That may be what you’re saying anyway, I just wasn’t clear. The “far enough to provide a transition” language is what threw me off.
I understand wanting to keep consistency between two closely spaced urban areas.
However, and I may be a little foggy on this, does this mean we should keep the urban classification between two urban areas that are say, 40-50 miles apart?
I only say this because it isn’t uncommon for some roads to be a Primary Arterial in an urban area, drop to a Minor Arterial on the rural map, then at some point drop down to a Major Collector.
For example, you have State Hwy 1 that is the main route through the middle of town A and is 4 lanes. Once it hits the city limits, it goes down to 2 lanes, and the rural map says it is now a Minor Arterial. A mile or so outside of town, the road has an interchange with an adjacent interstate, and on the other side of the interstate, State Hwy 1 becomes a Major Collector on the rural map. 30 miles down the road, it enters another urban area (town B), in another county, and becomes a Minor Arterial.
Now, the way I have been doing things is I would take the urban classification all the way to the interchange with the interstate, then beyond there, I would demote the road only down to a mH because it is a state highway. But you’re saying that it should be carried all the way to the other urban area as a MH?
No, that would only be appropriate if there weren’t a Major Collector portion at all. The moment it becomes Major Collector, Major Hwy is not an option (unless it’s a US Highway).
The way you’ve been doing it is good. In your example, I would carry the MH through to the Interstate, then continue as mH after that, even if it weren’t a state highway – the higher of the two types available for a Major Collector, because the road is Major Highway on both ends, and Minor Highway is the higher type available for Major Collectors.
I think I’m having a hard time explaining this clearly but I’m kinda pressed for time at the moment. Basically, if it would result in continuity – whether perfect or not – choose the higher option. By “imperfect continuity” I mean that, if it’s what’s available to you, having the road switch from MH to mH to, later, MH again makes more sense than MH to PS to MH.
Anyway, continuing it to the Interstate is a very good practice, and an important exercise in grid continuity, which is a concept I’ve been wanting to speak on for a while but which I haven’t had much time for yet.
I guess my main hang up/point of confusion is I was imagining that you could potentially convert a road to a major highway over a very long distance simply because it was a Primary Arterial through a city, when said road may not really be intended for that function by the DOT further down the road.
So let me pose one last question, if said road never became anything better than a Major Arterial after passing the interstate, never enters another urban area, and did not otherwise qualify to be a mH (ie., not a State Hwy, BR, LOOP, etc.) would you just drop the road to a PS anyway? Or maybe just carry the higher classification until its next intersection with another classified road?
Only when it’s a Rural Minor Arterial through that rural area, which does suggest a relatively high-traffic function, though perhaps not quite to the level of a Principal Arterial. Still, an arterial nonetheless.
Oh, I think I may have either misread or misunderstood your hypothetical.
URBAN ]] rural rural rural [[ URBAN
--Princ Art--]]-Minor Art---{Interstate}--Maj Coll--[[-Minor Art--
Major Major/Minor Minor/PS Minor
I reread it and I think this is what you’re saying – top row is urban vs. rural area; bottom row is corresponding Waze type. In this case, I would choose Major and Minor respectively for the two sections: Major to extend the urban grid to the Interstate intersection; Minor to give continuity between the two urban areas when the type in both urban areas is at least Minor Arterial. Is this making sense?
So following the above, say the second urban area isn’t there (for instance, it is a county road that at best intersects a state or US highway 10 miles away), I have been usually just going straight to the rural classification at the end of the urban area. Would it be more appropriate to keep the urban classification going, even though said road never enters another urban area, or just pick up the rural classification as I have been doing?
