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Road Types (USA) – comprehensive overhaul of drivable roads

Post by sketch
Quick link: Proposed revision to Road Types (USA) drivable types (Freeway, Highways, Streets)

Road types aren't just for show, they make a difference in the routing server. The server doesn't have the time or resources to look at every single street between where you are and your destination, so it uses road types for guidance in selecting the best route for you. Road types aren't everything — of course, Waze uses actual and historical traffic speed data to select the fastest route for you at a given time — but they are important. They show Waze which roads to check when looking at that traffic speed data. So setting the type too low can mean Waze doesn't consider a road which may actually get you there faster.


Freeways are a fact of life. While freeways are by design often the fastest way from A to B, we all know this isn't the case every time. Sometimes a freeway just isn't convenient. Other times, freeways are clogged with traffic, while surface streets flow rather freely. Sometimes both situations are faced — without traffic, maybe the freeway adds 5 miles to your route, but it's faster anyway; today, though, the freeway is backed up and taking the 5-mile-shorter route will save you time.

Freeways are the highest type of road in Waze, often assumed by the routing server to be the best alternative. Sure, they often are, but that isn't always the case. For Waze to consider other roads as viable alternatives, there need to be other relatively high type roads — Major and Minor Highways — in the area for Waze to consider, or else you might just end up on the freeway in that traffic jam anyway.

Further, road types are increasingly important for longer routes. Yes, Waze is designed as a commuter application, but it'll provide routes up to a thousand miles. I've used Waze on dozens of thousand-mile-plus road trips, and it's performed admirably. And some people just have long commutes. Well, as we know, many lower-type roads are not considered at all by the routing server for routes longer than a certain length. The longer the route, the higher the road type has to be. For travel within a state, Minor Highways could be enough. For travel through the States, you want at least a Major Highway.

The current rules for setting road types in the United States are based on the physical characteristics of the road and are somewhat nebulous. The vagueness of the standards leads to inconsistent application, with editors in different parts of the country using different criteria for choosing road types. This leads to an inconsistent user experience across the country, even within states. It's even led to disputes, with editors who disagree on what type best suits a particular road, switching the type of a road back and forth.


Luckily, the federal government has a solution for us. The Federal Highway Administration (FHWA) has come up with a set of standards by which every road in the country is judged: functional classification (very short explanation here). The functional classification of a road is determined both by the physical characteristics of a road and by the Average Annual Daily Traffic (AADT) — the number of cars that, on average, drive on a particular road each day. Each road is therefore placed in one of the functional classes; each functional class describes a particular usage scenario for the roads in it. The functional classification criteria are passed on to the several States, and each state's department of transportation in turn uses the criteria and their own research to gather information, to classify roads, and to publish maps showing the functional class of every road in the state.

The federal government further provides guidance to us by designating roads as parts of the Interstate Highway System and the United States Numbered Highways system. The roads themselves are built and maintained by the states; but in selecting the routes, the federal government identifies a network of important long-distance travel routes throughout the country. Finally, the government of each State (and D.C., and some territories) designates roads as parts of its respective state highway system; these routes are selected for their importance in travel within a particular state.

Luckily for us, functional classification and the various highway systems comport quite well with Waze's set of road types.
Functional class / highway systemWaze road type
FC: Interstates
FC: Other Freeways and Expressways (some)
HS: Interstate
Freeway
FC: Other Freeways and Expressways (others)
FC: Other Principal Arterials
HS: U.S. Highways
Major Highway
FC: Other Arterials
HS: State Highways
Minor Highway
FC: Major Collectors
FC: Minor Collectors
HS: County Routes
Primary Street
FC: LocalStreet
This system has already been put into place for testing in various metropolitan areas, including New Orleans and Detroit. Besides the clear improvement in definitiveness of road type selection, many other editors and I have noticed a marked difference in the performance of the routing server and in other aspects of Waze since implementing the systems.

Advantages
  • Waze is more likely to select the best possible route at the start, without you having to ask for alternatives
  • Waze is more likely to select alternative routes in the case of clogged freeways
  • The map display becomes more useful, showing the most important roads with thicker lines and at higher zoom levels — and, bonus, allowing you to see at a glance where the "downtown" area of a city is (examples: New Orleans; Detroit)
  • As said above, as a well-defined system, it does not allow for disputes and may make frivolous edits easier to discover
Disadvantages
  • Temporary: Currently, road type is the primary factor used to judge traffic jam highlighting. That said, I've been using Waze daily in New Orleans for months with this system in place and have not seen any instances of erroneous jam highlighting. Also, staff has announced that road type is soon to be replaced as the principal jam-highlight criterion with something else based on the actual jam-free speed of the road.
Many discussions have been had about the merits of such a system, and most editors have come out in favor of such a system. Experience will show that this system works, and it works well. It takes a lot of the guesswork out of editing, and it has the potential to improve routing considerably. In fact, many editors are using this system already in their states and areas.


Here is the proposed page: https://wiki.waze.com/wiki/Road_types/USA/Revision


Note: As you'll see, this doesn't cover non-drivable and non-public road types (parking lot roads, private roads, walking trails, etc.). While much of that section of the article does need revision, it should be carried out in another thread.
sketch
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Last edited by sketch on Thu Apr 17, 2014 5:34 pm, edited 1 time in total.
Reason: revision page link changed
ALL US EDITORS READ: New USA road type guidance
the guidance linked above is now almost a decade old, but the link gives me a laugh every time i see it, so it stays (:
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Post by sketch
Thanks for the input, all, I appreciate it.

With the next NA meetup looming as close as it is, of course I'm perfectly comfortable waiting until then before implementing it nationally.

Kent, I did take account of the recent-ish changes to the Overview section of the current page. I included some of that a few days ago. The rest is pretty much a wholesale change.

Regarding the US/State/County Highway correlation, I agree that that should be part of it, and it is. But that doesn't cover anywhere near everything; there are 55 mph suburban expressways which don't fit into any of those systems. I'm sure this isn't what we'd intend, but I've seen this pushed to its extreme in the Detroit area — where US Routes were Major Highway, state highways were Minor Highway, and every other county- or municipality-maintained surface-street thoroughfare was Primary Street, including that 55 mph expressway I mentioned. Routing left quite a lot to be desired. Like I said, I know that's not what we'd intend by that standard, but the point of including functional classification is to have definite answers for those roads as well.
PhantomSoul wrote: From what I understand, the higher road types in Waze are meant to narrow the network of possible routes to consider for really long trips - I would imagine we're talking 50+ miles in the scope of MH and Fwy, if I'm not mistaken. Many of the urban routes that New Jersey calls principal arterials are not meant to be principal arterials across the entire state or even across the multiple counties, like Waze is looking for with the higher road types, but rather just the principal arterial through that specific urban area. . . .

Maybe I have the objective of the road types totally wrong, but if they are for trying to single out roads appropriate for use in the middle of trips of certain distances, then urban arterials are a bad metaphor for Waze highways.
That's one function of higher road types, the other seems to be during the initial route pruning process. Cities have Freeways too — the highest type road — so if you give the server a couple Major Highway alternatives to choose from, it'll be more likely to "see" an alternative route in case of traffic on the freeway. Upgrading to functional classification — which, yes, means Major Highway on 35 mph roads with lights — added a third route to my daily commute besides the 2 freeway options. It only routes me along that route occasionally, when traffic is especially bad on the other two, but for those occasions it's worth it.

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.
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ALL US EDITORS READ: New USA road type guidance
the guidance linked above is now almost a decade old, but the link gives me a laugh every time i see it, so it stays (:
assistant regional coordinator • south central region • usa
waze global champ • beta leader • and more • new orleans

bye bye fuelly badge! i'm an EV guy now!

Post by SeveriorumPatrem
Following thread....

I am continuously surprised and a little disappointed with the frequency that somewhat major changes are implemented without the champs being given enough heads up to coordinate updates of our documentation in advance.

Log in, find "unpaved" in the road type in place of "4x4 dirt road", go do some research, and the consensus is "we don't really know how this works yet, but at least we think we know where they're going with it.... eventually."

I think you champs should be treated a lot better than that, considering how much you do for them.... for free. Thanks.
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Post by SanzClew
PesachZ wrote:I wrote that since we will not be the only ones reading this thread, and others later might be confused.
Excellent point, as always.
FzNk wrote:Sorry, I missed PZ's post and wasn't intending to dog-pile on the point.
LOL... i prefer the term smushing... it's all good.
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Post by SanzClew
From your PL in a post above, that segment has a list of AM's who can edit that in the box at the left - the screenshot below hows the link to click:

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Post by SanzClew
I'm coming into this late so this may have been discussed already. The new Private Roads section is really nicely done and helpful. I was, however, struggling to jump from that section to a discussion about driveway segments and couldn't find a link to that area in that topic. Eventually I scrolled down far enough to hit the special case section on that page.

Would it be feasible to briefly mention that some Driveways can be specifically shown as private roads and drop the link to the Driveways page in the bulk of the Private Roads paragraph?

Thanks
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Post by russblau
txemt wrote:
voludu2 wrote:Then the style/best practice for this should also clearly state that any MPs which arise as a result should be closed "not identified", just to be clear that we aren't going to let an MP tell us what to do.
No, don't ever close an MP as "not identified." IGNs get involved then.
Guidance on this in the wiki is now to the contrary. https://wiki.waze.com/wiki/Map_Problems ... e_Elements.
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Post by russblau
Well, I don't want to be a dog in the manger, but I still do not agree with the requirement to upgrade roads above their functional classification based solely on numbered route signage. But if the consensus is that that's the preferred approach, I guess I will live with it.

I would suggest, however, the following changes in the guidelines --

1. Under "Minor Highways," change the second bullet point to "Signed, numbered routes in state, D.C., and territorial highway systems."
2. Under "Primary Streets," change the second bullet point to "Signed, numbered county routes (and, in Louisiana, parish routes)."

We don't need to encourage anyone to go finding "secret" (unsigned) state or county highways and upgrading them based on something that is invisible and meaningless to the Waze user.
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Post by russblau
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.

The references to "county routes" are useless in Virginia, since we don't have them, and in most counties literally every street, from the eight-lane arterials down to the 200-foot dead end around the corner from my house, has a "secondary state highway" number that is absolutely meaningless in terms of Waze's mapping needs.
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