User:Westnordost/Proposed Resurvey Intervals

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I do plan to add an option in the app to ask "more often" and "less often", decreasing the delay by a factor or increasing the delay by a factor. So less than finding absolute values, it would be important to find relative values.

So, please, treat this page like a discussion page and add your 5 cent here.

Resurvey Categories

To have consistent estimations in which intervals features should be checked, it may be helpful to first gather experience values over things like "how often do muncipalities revise their traffic concept?", "how often do shops change owners?", "how fast does a road quality degrade if not maintained?".

How often do muncipalities revise their traffic concept?

What's your experience?

  • Kraków, Poland - there are constant changes, with maxspeed/oneway/parking lane etc changing often and on a widespread scale. Some of them were events happening once (like administrative decision obligating local government to remove thousands of illegally marked parking spaces or enlarging paid parking zones), but this once-off events keep happening Mateusz Konieczny (talk) 22:27, 26 July 2020 (UTC)
  • Netherlands: Most existing roads largely seem to stay the way they are. Most often when roads are restructured (changed restrictions / upgrades), it's in places where the roads were built to capacity like in town/city centers or on traffic hubs nearby (or leading to) highways. Things like oneways are usually only changed when the traffic concept is revisited. Maxspeed might change more often, especially after a road is newly built and there's a new situation they'll start with a lower speed, but 80% of the time when someone maps the speed, it too stays that way for a long time. To me, getting more complete maxspeed data everywhere would be more valuable than swamping people in validation tasks. --Lucgm (talk) 00:23, 27 July 2020 (UTC)
  • Spokane County, Washington, USA: Changes other than new construction and paving unpaved roads are rare. Speed limits and lane counts are generally stable. --Carnildo (talk) 07:24, 27 July 2020 (UTC)
  • Hamburg, Germany: How much is made seems to depend much on the current government. In the 2000s, infrastructure wasn't much changed or maintained, since 4-8 years roads are being revised, roundabouts added, cycle lanes added (and cycle tracks removed), timed 30-limits implemented etc --Westnordost (talk)
  • Cincinnati, Ohio, United States: This is one of the metropolitan areas with the most urban sprawl in the country. In the outer suburbs, a few roundabouts or turbo roundabouts are replacing traffic lights every year along county-maintained arterial roads, and numerous four-way stops with blinkers are giving way to traffic lights. Each year, several arterial roads are either widened or given landscaped medians where there used to be center turn lanes. Every couple years, a major intersection gets reconfigured with a novel junction concept, most of them in transportation improvement districts. Individual speed limit changes are rare, but once every decade or so, a city or the whole state will revise all its speed limits upwards or downwards at the same time (with exceptions). – Minh Nguyễn 💬 00:31, 31 July 2020 (UTC)
  • Dallas, Texas, United States: The northern boundary of this metropolitan area creeps northward faster than the southern coastline of Louisiana. I come back every year and it seems like another county's worth of farmland has been swallowed up by new suburbs. Texas is very aggressive in building freeways to support this kind of growth. I'm not sure StreetComplete is the best way to keep up with the pace of change in this area. – Minh Nguyễn 💬 00:31, 31 July 2020 (UTC)
  • San José, California, United States: In general, road configurations are very stable here, because the valley has already been built out as much as possible. However, in recent years, there has been a focus on road diets and improved cycling infrastructure. Each year brings several more miles of bike lanes in the county, some of it of the quick-build variety. [1][2] – Minh Nguyễn 💬 00:31, 31 July 2020 (UTC)
  • Wuppertal, Germany: I feel like the concept itself is pretty stable, slowly moving from one target to another in intervals like 10 years. 10 years ago it was like 'get the trucks out of the city center' and now it's 'get some cycling infrastructure in place. While the concept itself changes slowly, the changes on the road are constant without any clear rhythm or focus on a special time, like before votes or in summer... it's more a constantly evolving process. The stuff most often changes are actually speed limits. I feel like they get changed all the time right now. The other thing is updates to the public transport infrastructure and traffic signals which get a lot of attention for including reliefs for blind people. Cycle ways and cycle lanes do also pop up quite often. Those are the stuff I would recommend checking once a year actually. So if there's no cycle way, check once a year if one popped up, if there's no reliefs on the ground for blind people, check once a year if it get installed etc. while the other way around is quite rare, so maybe we want give the one values more attention. --RubenKelevra (talk) 22:27, 16 September 2020 (UTC)

Takeaway from experiences: Bigger changes in infrastructure seem to be somewhat irregular / "gig"-based. I see no way to account for that easily, so we are back at checking if something changed every X years. Things are very unlikely to change several times during one legislative period (in most places, about 4 years), so I would set the re-check-interval for things that likely change during a revision/redevelopment of a traffic concept/quarter to 4 or even 8 years. --Westnordost (talk)

How often do shops change owners?

What's your experience?

  • Some shops (in apparently poor locations) cycle through owner at least once a year, but many are stable. In general, if shop is young that it is likely that it will disappear. Shops present for long have far lower attrition. Though opening hours are far more unstable and checking opening hours indirectly checks whatever shop exists Mateusz Konieczny (talk) 22:25, 26 July 2020 (UTC)
  • Netherlands, some experience in Nordrhein-Westfalen (Germany): Takeaway-oriented places: some almost yearly, others never. Chains are quite stable, maybe one change per 5-10 years. Stores owned by just one person with no other branches can be as stable, but another significant part goes out of business within a year or two. --Lucgm (talk) 00:23, 27 July 2020 (UTC)
  • Spokane County, Washington, USA: Depends on the type of shop. Ethnic-food restaurants are probably the least stable, often changing owners (and cuisines) every few years, while stores that are part of a chain are stable on a timescale of decades. In general, the longer the store's been there, the less likely it is to change. --Carnildo (talk) 07:24, 27 July 2020 (UTC)
  • Perhaps a useful proxy would be a study about overall business startup and closure rates, such as [3]. But geography and POI type are significant factors, and I don't think these studies count the opening or closure of a store branch, so I'm not sure if it's granular enough for this purpose. – Minh Nguyễn 💬 15:27, 27 July 2020 (UTC)

Takeaway from experiences: Some businesses pop up and vanish fast, others stay a very long time. It could be that small places such as (fast-food) restauraunts have a shorter average life expectancy. Overall, it is difficult to quantify which places to ask more often for and which places to ask less often for - maybe based on assumed size (fast-food, kiosk, convenience shorter intervals?). I'd set the resurvey interval maybe to 1-2 years in general for businesses but for opening hours to 1 year if it is fast to answer when they didn't change (which it is, thanks to Mateusz' implementation). --Westnordost (talk)

How fast does a road quality degrade (if not maintained)?

What's your experience?

  • Depends on traffic, but roads with heavy traffic are also maintained. asphalt needs decades to crumble into surface=compacted or surface=gravel. But to drastically change tracktype it is enough for single logging operation to take place (it can be also easily upgraded, sometimes bigger logging operations will involve upgrading existing tracks) Mateusz Konieczny (talk) 22:30, 26 July 2020 (UTC)
  • Netherlands: um, not fast enough that I ever consciously noticed it. I think we spend a lot of money on good infrastructure though, roadworks in Germany take half a year for some surface work and are also done at a much lower interval, and in Belgium the maintenance interval is measured in generations. But in 4+ years of regularly visiting the same places in Belgium and Germany I also didn't notice any of their roads degrading significantly enough to take note of, just the already-degraded roads that remained degraded or had some patches put on them. --Lucgm (talk) 00:23, 27 July 2020 (UTC)
  • Spokane County, Washington, USA: If the city's pavement-age maps are to be believed, very slowly for low-traffic roads (according to the map, the asphalt in front of my house is 50 years old, and still in reasonable condition). High-traffic roads need (and get) frequent maintenance. Unpaved roads degrade rapidly (a freshly-graded road will drop in smoothness from "intermediate" to "bad" in a matter of months), which is why they get smoothed at least once a year. --Carnildo (talk) 07:24, 27 July 2020 (UTC)
  • Chiang Mai, Thailand: They re-do major roads every 4 years or so but re-doing them just consists of scraping off the current asphalt and putting on a new layer which is done within one day or so. Reason seems to be that it is more cost-efficient to do cheap roads that degrade fast rather than high quality roads that need less maintenance. I think this kind of road-building is rather the default throughout the world because the situation in the western world with such high cost for labour is rather unique. It could be that climate conditions are part of the reason as well. --Westnordost (talk)
  • Cincinnati, Ohio, United States: I think most counties, townships, and municipalities in the metropolitan area have comprehensive road resurfacing schedules. Road salt damages pavement so much that merely filling potholes will make the road surface uncomfortably bumpy after a few years. A mostly residential suburb like Loveland resurfaces probably about a fifth of the road mileage in the city every year. This includes quiet residential streets (highway=residential), which aren't immune to the effects of weather and salt. [4] – Minh Nguyễn 💬 00:11, 31 July 2020 (UTC)
  • San José, California, United States: Here in the Sun Belt, road salt is a nonissue, so a coat of asphalt on a residential street will last several years without a problem. However, due to heavy traffic, the arterial roads and highways go from freshly paved to uneven and pothole-riddled within a couple years. For budgetary reasons, city-maintained streets are generally better maintained than county-maintained roads, which in turn are better maintained than state highways. – Minh Nguyễn 💬 00:11, 31 July 2020 (UTC)

Takeaway from experiences: I think I asked a slightly wrong question. This is not that much of a category because it only concerns road surface. Let's ask another, see below. Maybe the answers will be the same, but anyway. However, a takeaway is that big roads are likely to change much more often than residential roads while unpaved roads degrade more often. So maybe reasonable would be for smoothness:

  • ground roads: 1 year
  • unpaved roads: 2 years
  • paved roads: 4 years
  • for low traffic or no car traffic ways (highway ~ footway|path|cycleway|track|residential|living_street|service): 2x less often
  • for high traffic roads (everything up from tertiary): 2x more often

--Westnordost (talk)

How often is a road being digged up for maintenance? (repairs on sewage, road surface, sidewalks & cycle tracks, power and telephone cables, glass fibre,...)

What's your experience?

  • Silezia, Poland - on minor roads it may be once 40 years (famous case in my family as sewage renovations started immediately after road surface had full replacement). Mateusz Konieczny (talk) 14:14, 29 July 2020 (UTC)
  • Kraków, Poland - Once every 8-10 years on bigger roads? Once every 15 years on minor roads? power/telephone/internet cables are typically handled without ripping surface. There is a bit of surge of construction of heat pipes. Such construction is nowadays typically coordinated with replacing road surface. (interval stated based on what feels right, without digging into archives when roads were renovated) Mateusz Konieczny (talk) 14:14, 29 July 2020 (UTC)
  • Spokane County, Washington, USA: individual lanes are closed on a regular basis, but full-road closure is rare. The city's six-year maintenance plan calls for just four long-duration construction closures, and the county typically adds another two or three a year. Total reconstruction, even for major roads, only happens every few decades. --Carnildo (talk) 18:45, 29 July 2020 (UTC)
  • Giessen, Germany: Especially in the past 2 years all over the city a lot of roads (both in low traffic zones and high traffic streets) have been partially digged up for maintenance. This usually just affected parking for roughly 2-5 months in low traffic residential zones or speed limits for anywhere between 2 and 10 months in more high traffic streets. Within these months in the low traffic zones these streets usually would be completely closed for a few weeks while they move to another part of the street. Full street closure is more rare and I would say happens on average roughly one time a year for roads I drive through. (sometimes more, sometimes less, driving for 4 years) --WebFreak (talk) 07:56, 30 July 2020 (UTC)
  • Wuppertal, Germany: Road construction (minor) is extremely common, while full road closures are like common like every 2-3 years. I feel like some infrastructure just get currently replaced all over the city. I was wondering if forcing a resurvey of all details on a street would make sense, when the street got closed for construction. Most of the time the bus stations, sidewalks etc gets replaced, new lights get installed and pedestrian crossings gets moved, redesigned and details changed. If SC is doing the quest 'construction finished', it could either remove the check_date values or set them to a specific value like 'no' to force an immediate resurvey of the details around the street. --RubenKelevra (talk) 22:33, 16 September 2020 (UTC)


This is the second iteration of the proposed intervals, grouping the quest types into rough categories (see above) and taking into account the input done in the first table

Let's aim at a confidence of 75% that the information on OSM is up-to-date. So if we assume that a thing might change within 16 years, we should check the thing every 8 years so that it is on average outdated 4 years, thus up-to-date on average 75% of the time. In short, we want to check things twice as often as we expect it in average to change by default. In StreetComplete, there will be an option to check things twice as often as the default (88% confidence that things are up-to-date) or twice less often (50% confidence that things are up-to-date) as the default. I think 75% is a reasonable default.

QuestType Time to answer quest in SC Interval Category Interval adjustments and comments
AddBenchBackrest 1 Major
AddBikeParkingCapacity 2 Minor Changes quite often, I would say that in given year there is 3-8% of chance for change (Kraków). Mateusz Konieczny (talk) 14:19, 29 July 2020 (UTC)
Resolved: Changed the category to muncipal maintenance because adding/removing some bicycle stands is not big --Westnordost (talk) 11:17, 14 July 2020 (UTC)
AddBikeParkingType 2 Major whellbenders I would say that about 4% each year disappears, some are also changed into wheelbenders, about 1% of other parking types disappears each year (Kraków). I would recommend 5 to 10 years Mateusz Konieczny (talk) 14:19, 29 July 2020 (UTC)
In my experience, wheelbenders are not replaced by stands but wheelbenders pop up and vanish and stands pop up (and maybe vanish) - at (slightly) different places. One type of bicycle stand is not "upgraded" to another. So basically that users should re-answer this question would basically be the "Is it still there though?" question, quite like the "Opening hours" question is for businesses. So my suggestion would be to only ask again for wheelbenders and stands --Westnordost (talk)
AddCycleway 3 Major Every 8 years feels a bit soul-crushing given that it is quite irritating to reply. With showing what is answered and allowing to select yes/no it would be probably OK. Mateusz Konieczny (talk) 14:35, 29 July 2020 (UTC)
Resolved: Changed time for muncipal redev to 10 years --Westnordost (talk)
AddBoardType 2 Major
AddBusStopShelter 1 Minor If it already has a shelter, ask 4x less often --Westnordost (talk)
MarkCompletedBuildingConstruction 1 Construction Not relevant, this is already a resurvey quest :) Mateusz Konieczny (talk) 14:35, 29 July 2020 (UTC)
MarkCompletedHighwayConstruction 1 Construction Not relevant, this is already a resurvey quest :) Mateusz Konieczny (talk) 14:35, 29 July 2020 (UTC)
AddCrossingType 2 Major
AddVegan 1 Business Don't ask if previously "only", because it is part of their identity. If it changes, it is probably a different business then (input by CamelCaseNick). Ask 2x less often if previously "yes", similar reason (based loosely on input by Lucgm)
AddVegetarian 1 Business Only ask if previously "no", because it is part of their identity. If it changes, it is probably a different business then (input by CamelCaseNick). Ask 2x less often if previously "yes", similar reason (based loosely on input by Lucgm)
AddHandrail 1 Minor If it already has a handrail, ask 4x less often. (A handrail can still decay or be destroyed) --Westnordost (talk)
AddInternetAccess 2 Business Asked 2x less often because it is only asked for hotels and the like, so for bigger businesses which change less often (based on input by Lucgm)
AddMaxSpeed 3 Major Ask 2x less often for non-main roads --Westnordost (talk)
AddMotorcycleParkingCapacity 2 Major
AddBikeParkingCover 1 Major
AddOpeningHours 5 Business x2 less often on shops that are currently open 24/7 (input by Mateusz Konieczny) or that have same opening hours throughout the work week (f.e. Mo-Fr) and no lunch break (input by Westnordost) because this indicates a larger business
AddParkingFee 2 Major
PostboxCollectionTimes 4 Business every 2 years (Input of sundew, someone who likes to keep postboxes up to date)

Perhaps a question of whether the postbox is still physical present can be asked first or at more frequent intervals, which would be a 1-tap question. --Kathleenlu([[(User talk:Kathleenlu[talk]])

AddRailwayCrossingBarrier 2 Major
AddRecyclingContainerMaterials 2 Major
AddCyclewaySegregation 1 Major
AddCyclewayPartSurface 2 Major ask 2x more often if not paved --Westnordost (talk)
AddFootwayPartSurface 2 Major ask 2x more often if not paved --Westnordost (talk)
AddPathSurface 2 Major ask 2x more often if not paved --Westnordost (talk)
AddRoadSurface 2 Major ask 2x more often if not paved --Westnordost (talk)
AddTactilePavingBusStop 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)
AddTactilePavingCrosswalk 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)
AddTracktype 2 Major ask 2x more often if not tracktype=grade1 (~ not paved) --Westnordost (talk)
AddTrafficSignalsButton 1 Major
AddTrafficSignalsSound 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)
AddWayLit 1 Major Add 4x less often if previous answer "yes". Or don't ask at all? Never heard of street lamps being disassembled --Westnordost (talk)
AddWheelchairAccessOutside 1 Major
AddWheelchairAccessPublicTransport 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)
AddWheelchairAccessToilets 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)
AddWheelchairAccessToiletsPart 1 Minor Don't ask again if previous answer "yes" --Westnordost (talk)

Time to answer:

  1. Just one tap
  2. Enter a number or select a picture
  3. Select several pictures or make several choices
  4. Complex form
  5. Very complex form

The more complex a form, the more cautious we need to be in asking the question too often. Also, the more complex a form, the more it is worth to invest the time to show the current value to the user before prompting them to reenter the data (for example, opening hours).

Interval Categories:

  • Construction: 6 months
  • Business: 1 year
  • Minor: 2 years - Smaller repairs on infrastructure such as sewage, telephone and power cables, upgrading public transport stops for accessibility etc.
  • Major: 8 years - Larger works that are part of a (new) traffic/city planning concept/project

As described above, these should be roughly half the time one may expect a feature/property to change.