explain xkcd - User contributions [en]

Talk:2728: Lane Change Highway

2023-04-17T19:02:01Z

162.158.90.174: Just a question

There's a section of the M25 motorway around London which does this... Never did like it. [[Special:Contributions/172.70.85.201|172.70.85.201]] 07:14, 24 January 2023 (UTC)
:I hope you are kidding ;-) Although there are some funny histories about that road. For instance Good Omens by Neil Gaiman and Terry Pratchett. (Now a series - see [https://youtu.be/M0S3a32RzEo?t=112 Crowley Creates (and Destroys) The M25 - Good Omens]. :-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:25, 24 January 2023 (UTC)
::Not quite the same thing, but in my city there are many roads that run through a substantial portion of town, occasionally varying the number of lanes by either adding a new one immediately following an intersection, or converting an existing lane to turn-only at an intersection, and then after the intersection only having as many lanes as were permitted to travel straight through the intersection. But for one or two of these roads, in order to drive the full length of it, you will have to make several lane changes in the same direction (I can't recall whether it's to the right or to the left), because through one intersection where only a single lane is able to go straight, that same lane eventually ends up becoming a turn-only lane at another intersection somewhere farther down the road. It's obviously not like Randall's example, but it is a mild annoyance when you end up driving that stretch of road often enough to notice it. [[User:Dansiman|Dansiman]] ([[User talk:Dansiman|talk]]) 23:18, 24 January 2023 (UTC)

:A lot of highways in France do something similar. At every ascend, the ascending traffic gets its own new lane, presumably to keep ascending cars from doing merging manoeuvres. To keep the same number of lanes, the leftmost lane merges into the adjacent lane before the ascend. So if you simply stay on your lane, you kind of drift to the left with every ascend. I am not sure if this really helps to cut accidents, but I think it is a clever solution at least for some accident-prone ascends. [[Special:Contributions/172.71.160.36|172.71.160.36]] 08:32, 24 January 2023 (UTC)
:: That sounds like using passing lanes, so that slower traffic, with more difficulty going up the hill, like transport trucks, will use the outside lane and faster cars will be on the inner lane, to not be significantly impeded by the slower traffic. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 14:44, 24 January 2023 (UTC)
::: That sounds odd to me. Even taking into account that my "left lane" is the US/French "right lane" (the one close to the kerb, furthest from the median/dividing line), "outside lane" to me means the overtaking or 'fast' lane, with "inside lane" the one most to the roadside (the driver is on the outside edge of a vehicle, assuming the usual local parity between Foo-side-driving and Bar-side-driv''er'').
::: But I do know some roads (on undulating landscapes) that on the bottom of an uphill section will have a new road-edge lane (vehicles expecting to go slow will filter into that, hopefully without crawling past a marginally slower climbing vehicle to get ahead of them) and then, near the top of the rise, the centre-lane is forced back into the left just in time to encounter the end of the contrary direction's two-lane rise up ''its'' hill.
::: That is, three lanes for most of the time, the centre being assigned to the direction going uphill on any given stretch (a permant type of 'Tidal Flow' traffic management system). [[Special:Contributions/172.71.178.137|172.71.178.137]] 19:04, 24 January 2023 (UTC)

Saved the image to the wayback machine here https://web.archive.org/web/20230124073752/https://xkcd.com/ [[User:Mushrooms|Mushrooms]] ([[User talk:Mushrooms|talk]]) 07:41, 24 January 2023 (UTC)
:Doesn't that happen automatically? I like they are there, but do webcrawlers not manage that on a daily basis? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:17, 24 January 2023 (UTC)
::Huh, didn't know that. Better safe than sorry! [[User:Mushrooms|Mushrooms]] ([[User talk:Mushrooms|talk]]) 08:33, 24 January 2023 (UTC)
:::Indeed, it doesn't hurt to do so. In fact, xkcd is actually archived every day, multiple times. I've also configured my bot to archive xkcd and explainxkcd when a new comic comes out automatically through archive.org. —[[User:Theusaf|theusaf]] ([[User talk:Theusaf|talk]]) 21:35, 24 January 2023 (UTC)

It's really a very wide single-lane road. The left lanes originate from the edge of the road so no cars feed into them, and on the right side once you merge there is no where to go except to merge into the next right-hand side, so the net effect is that the road is 4 lanes wide, but is functioning as a single-lane road. That assumes everyone is entering from the right side. But I guess they could be entering from the left but still in a very short time all cars are on the right. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 12:24, 24 January 2023 (UTC)

This is very similar to major roundabouts, in the UK at least, that have a spiral outwards. If entering a four-way junction (and there can be more feed-offs than that) , you may be invited to assume one of three entry lanes (as soon as the feed-in is wide enough to accommodate them) for left (the side of the road upon which we drive), forward or right that lead onto one of three lanes going clockwise round the island.
 (Sometimes the left-lane becomes marking- or even curb-separated from the island lanes, effectively skirting the island so there's no waiting for traffic on the island to pass. It merges with the feed-out lane, or becomes a two-lane carriageway direction, some useful distance from the junction.)
 On safely entering the junction (by giving way to anything already on it ''or'' being filtered by traffic signals), the semi-perpendicular lane markings (oblique crosses at the lane-edge intersections) guide you to the outer/inner or any median encircling lane which, as each outlet is passed, shifts over by one with a new 'inner' lane for that latest input road's "(almost) all the way round" traffic. (For some junctions, 180 degree change of travel is also a necessity, e.g. due to no cross-traffic (right-hand turning) possible on the lead up to the island, but a sub-junction comes off it in that direction anyway.)
 It tends to work best on the rounder roundabouts with periodic entry/exit points, or on the truly huge ones that act like a town-centre one-way inner ring-road, only without the town. When there's a large complex with straights and curves, the guiding lines (especially across the 'crosses' might not be so obvious (if they are for the first car on the road, the one immediately behind might not have sufficient sight of the outward jinks in the indicated path and lose track of which path they should be on (especially if it is their first use of the junction) and the cross-overs can get worn and/or dirtied to make it less obvious), so inevitably there's lane-drift (and ''more'' wear/obscuration of the lane-guides).
 But, in general, with only accidental merging needed ("no, not this exit, it's the next one... there's nothing behind, so quickly...") and continuous lane-generation (to which the rarer all-the-way-round traffic can shift over into), I think there's a parallel. But this not being the inspiration or reference. [[Special:Contributions/172.71.178.65|172.71.178.65]] 13:12, 24 January 2023 (UTC)

I feel like this comic was posted later in the day than usual. It would be interesting to see a graph of what time of day comics were posted in (ignoring the day of posting, just in hours since the previous midnight EST) [[Special:Contributions/172.69.68.66|172.69.68.66]] 14:41, 24 January 2023 (UTC)Bumpf
:Yes, it was very late, after midnight EST. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:56, 24 January 2023 (UTC)

I personally would LOVE this road, as I would stay to the left and floor it. [[User:SDSpivey|SDSpivey]] ([[User talk:SDSpivey|talk]]) 15:30, 24 January 2023 (UTC)

Dang, I must have missed Randall visiting Cracow. Swerving lanes are the landmark here. One example: [https://www.google.pl/maps/@50.0294056,19.911734,3a,75y,244.95h,92.61t/data=!3m6!1e1!3m4!1sXOl1SrYQeSajOc3VCPr24A!2e0!7i16384!8i8192] Follow the road to find another. -- [[Special:Contributions/172.68.138.74|172.68.138.74]] 09:22, 25 January 2023 (UTC)

Someone who knows what a magnetic declination is should add that to the explanation [[Special:Contributions/162.158.186.94|162.158.186.94]] 17:47, 25 January 2023 (UTC)

Is it normal for the text under the image to have weird shadows like this text has? [[User:anonymous|anonymous]]([[User talk:anonymous|talk]])
([[User talk:SDSpivey|talk]])

2308: Mount St. Helens

2020-05-20T22:41:55Z

162.158.90.174: /* Explanation */

{{comic
| number = 2308
| date = May 18, 2020
| title = Mount St. Helens
| image = mount_st_helens.png
| titletext = It's a good mountain but it really peaked in the 80s.
}}

==Explanation==
{{incomplete|Created by AN OVERBLOWN MOUNTAIN. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic marks the 40 year anniversary of the {{w|1980 eruption of Mount St. Helens|May 18, 1980 eruption of Mount St. Helens}} that killed 57 people. It was a Monday so a normal release day could be used to mark this event.

It shows a graph of the height of the mountains in the {{w|Washington (state)|state of Washington}} as a function of time over the last 100 years. The only mountain to change its height significantly over this time period is {{w|Mount St. Helens}}, which the comic is named after. It is also the only black line as all other (30?) lines are gray.

Mount St. Helens is a {{w|volcano}} that famously and explosively erupted in 1980. Millions of tons of earth were blasted from one face of the mountain all over the surrounding countryside. After it was over, the peak of Mount St. Helens was no longer the 5th highest in the {{w|Washington (state)|state of Washington}}, having lost approximately 1,300 feet (400 m) in height (from 9,677 ft (2,950 m) pre-explosion to 8,363 ft (2,549 m) post-explosion).

The comic shows an rare event that had major effect and was predictable in hindsight, but would have surprised an observer that is just tracking the height of Mt. St. Helens in a non-representative timeframe. Such an event is called a {{w|Black_swan_theory|Grey Rhino}} event.
Interesting the horizontal axis shows an observation data period between 1920 and 2020. During this observation period both the 1918 {{w|Spanish flu}} and 2020 {{w|COVID-19 pandemic}} (each also Grey Rhino events) could have been overlooked in a similar way.

Currently, the 5 highest {{w|List of mountain peaks of Washington (state)|mountain peaks in Washington State}} are {{w|Mount Rainier}} (at 14,411 ft or 4,392 m), {{w|Mount Adams (Washington)|Mount Adams}}, {{w|Mount Baker}}, {{w|Glacier Peak}}, and {{w|Bonanza Peak (Washington)|Bonanza Peak}}. As shown in the comic, Mount St. Helens was the 5th highest, but now has fallen to #52 (using a {{w|topographic prominence}} cut-off of 300 m (984 feet)). Only mountains above 8,000 feet (2,438 m) are included, with the graph topping at 15,000 feet (4,572 m), 600 feet (182 m) above the highest mountain. There are 92 peaks above 8000 feet in the state, so not all are included and the lines are not really distinct below 9000 feet. Seems like there are less than 30 lines drawn. Of course it says Mountains not Mountain peaks, but there are only four mountain ranges in Washington with peaks above 8000, so he must mean peaks!

Technically, the other mountains may be fluctuating in height as well, due to erosion or the movement of Earth's tectonic plates, but this phenomenon should not be visible on the time-scale and vertical resolution that Randall has plotted.  Precision GPS measurements of various peaks in Washington have only been available since 2010, and it's likely that the primarily volcanic mountains of Washington experience significant but comparatively slight variations throughout the year due to snowfall, melt, or the pressure of swelling magma inside volcanic cores. These changes go largely unmeasured, while the mountains continue to appear equally physically unchanging and imposing both in person and from a distance.
Source: [https://www.seattletimes.com/seattle-news/how-tall-is-rainier-really/ Seattle Times]. So while the comic does appear to show some slight fluctuations in height for mountains, that is more likely a side-effect of the comic's free-hand drawing style than an accurate reflection of any real fluctuations.

The title text is a play on the term “peak” meaning both the highest point of a mountain and also the optimal, most famous or most impressive stage of a trend; for instance: "The band Rolling Stones really peaked in the 80s."

==Transcript==
:[Caption above graph:]
:Heights of mountains in Washington State
:Over time

:[A graph is shown with close to 30 horizontal gray lines which seem not to change much, if any, as they go from left to right. Only the top 6 gray lines are distinctly separated from others. The top line is way above the second line which again is far above the next two that are close together. Two more close together is somewhat further down, and just below them the rest of the lines follow in close proximity down to the bottom of the graph. A single black line is also shown. It begins as the fifth highest line, just above the two last mentioned above. It, like all other lines, goes horizontally, but only three fifths of the way across the graph – then it immediately drops down well below most of the other lines (at 1980) and levels off, continuing on its horizontal path. There is a caption above the graph, and both Y-axis and X-axis has labels. For the Y-axis there is a tick for every label, for the X-axis only every 2nd tick has a label. A unit is given on the top label on the Y-axis.]

:[X-axis:]
:1920 1940 1960 1980 2000 2020

:[Y-axis:]
:15,000
::feet
:14,000
:13,000
:12,000
:11,000
:10,000
:9,000
:8,000

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Timelines]]
[[Category:Geology]]
[[Category:Volcanoes]]

Talk:2281: Coronavirus Research

2020-03-16T19:16:22Z

162.158.90.174:

I don't think constantly refreshing the main page for 10 consecutive hours to get the first comment is healthy either, but I haven't found any studies confirming this. I think I'll refresh the CDC's website for a couple days to see if they add any articles on this. [[User:Unpopular Opinions|Goodbye, world!]] ([[User talk:Unpopular Opinions|talk]]) 18:33, 16 March 2020 (UTC)

The more I read about the issue, the worse my headache gets. I don't think I have Corona, but I'm starting to think there's also a memetic virus around with physical symptoms. I don't want anyone else to catch it from me, though; I'm just warning you all so you can make sure you don't get exposed to it. Tell everyone you know! [[Special:Contributions/162.158.90.174|162.158.90.174]] 19:16, 16 March 2020 (UTC)

Talk:2280: 2010 and 2020

2020-03-15T22:50:06Z

162.158.90.174:

Please maintain your distance in these comments. No comments within 6 vertical inches of other comments, please. And any in-comment sneezing or coughing will result in your account being banned for a period of 3 weeks. [[User:N0lqu|-boB]] Achoo! [[User:Bischoff|Bischoff]] ([[User talk:N0lqu|talk]]) 21:09, 13 March 2020 (UTC)

If the above information was new to you, please take this concise pamphlet. [[Special:Contributions/172.69.250.58|172.69.250.58]] 23:17, 13 March 2020 (UTC)

Maybe we should add a section on what holo-banshees are? That could be useful. [[Special:Contributions/162.158.58.183|162.158.58.183]] 01:51, 14 March 2020 (UTC)
:Since Holo-banshees are something Randall made up, that could be difficult. LOL! All we have is the name, and that's already explained. Though since the explanation talks about how this wouldn't make sense if they're present in EVERY household I'm somewhat inclined to add "therefore this is probably only a common problem, like rats, ants or cockroaches today." :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 05:09, 14 March 2020 (UTC)
:: Well, it says " often " there are holo-banshees. Not always or nearly. Banshees are female Irish vocalists who predict a death in the household, so I will assume that The Corrs joined the current mini-trend for touring your music act as a " hologram " and it got out of hand in some way. Robert Carnegie rja.carnegie@gmail.com [[Special:Contributions/141.101.69.5|141.101.69.5]] 11:00, 14 March 2020 (UTC)
:::I think they're like asbestos. Perhaps at one time considered a good idea (insulating/advanced indications of life-threatening household situations) but later on discovered to have unwanted properties forcing complicated handling procedures to make them safe. In the one case, the shedding of fine carcinogenic dust, in the other perhaps the 'holo' emits excessive intensities of certain wavelengths of light that are directly or indirectly an environmental biohazard. Sealing in situ may be the optimal situation. If, say, the non-corporeal (i.e. unmovable) holo-banshee must be sealed within an asbestos container, which must itself be safely coated then that would easily provoke the scenario hinted at. [[Special:Contributions/162.158.94.14|162.158.94.14]] 15:32, 14 March 2020 (UTC)

:I find the entire section about Holo-banshees ridiculously off-topic. It doesn't add anything to understanding the comic and should probably be removed. umläute [[Special:Contributions/162.158.94.122|162.158.94.122]] 21:43, 15 March 2020 (UTC)
::You say that now. But what about in a few comics time, when there may arise a clear and urgent need for an entire Category:Holo-banshees, eh? (Srsly, it's a potential "what's that about, then?" question by those who think they are missing a reference. Even if the answer we have to give is "apparently nothing".) [[Special:Contributions/162.158.90.174|162.158.90.174]] 22:50, 15 March 2020 (UTC)

1925: Self-Driving Car Milestones

2017-12-06T19:03:22Z

162.158.90.174: /* Transcript */ Use bullet list

{{comic
| number = 1925
| date = December 6, 2017
| title = Self-Driving Car Milestones
| image = self_driving_car_milestones.png
| titletext = I'm working on a car capable of evaluating arbitrarily complex boolean expressions on "honk if [...]" bumper stickers and responding accordingly.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

:This comic is a list of milestones for self-driving cars. Some have already been achieved, others are still being worked on, while others are facetious "milestones".
- automatic emergency brakes : this is another reference to how hard it can be to program human-obvious stuff (add link https://xkcd.com/1425/). A self driving car has to be able to distinguish a danger (cliff, person on foot, other cars coming the wrong way/doing weird stuff) from either the side of the road, the background, the other cars or even a light pole safely standing on the side of the road. Then the car also has to decide whether turn around, just slow down (as danger is not imminent) or actually do the strong brake (and optimally decide what would be the most effective, taking into account weather conditions, road type and traffic). There are big potential advantages for self driving cars, in case of success : computers don't panic, would have faster reaction times than humans, and would have safer "reflex-ideas" (rephrase? would do a better choice of action than a human that maybe doesn't know the wisest reaction) than humans (add link https://en.wikipedia.org/wiki/Autonomous_car#Safety)

- sometimes, especially on highways where road delimitations might be faint or absent (https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Route_66_2073773569_7b3fae3b91_b.jpg/220px-Route_66_2073773569_7b3fae3b91_b.jpg) or when lane markings could have faded away, a self driving car programmed to pilot based on road markings would have issues holding to the good side of the road. this is a bigger problem than in cities as cars move faster on highways, so the danger detection mentioned above might not manage to detect danger in time while breaking or avoiding the obstacle needs to be anticipated much more.

- already implemented in recent normal cars, that feature is important for the car not to stay in the road after use [citation needed], and is sometimes considered as a difficult maneuvre by to-be-drivers (citation?) as it requires a good "feeling" of the car dimentions, as well as of distances and maneuverability of the car. (the latter parameters being easy to compute, with radar and back-camera aide, is made rather easy for computers (citation?))

-

:The [https://en.wikipedia.org/wiki/Trolley_problem trolley problem] is a well-known thought experiment in ethics, in which a person must choose between passively allowing several people to die, or actively causing a single person to die. Such a choice could plausibly be forced on the computer of self-driving car. For example, if the car could avoid a high-speed collision only by running down a pedestrian.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

Upcoming and recently-achieved self-driving car milestones

* Automatic emergency braking
* Highway lane-keeping
* Self-parking
* Full highway autonomy
* First sex in a self-driving car
* Full trips with no input from driver
* Full trips by empty cars
* An empty car wandering the highways for months or years until someone notices the credit card fuel charges
* Cars that read other cars' bumper stickers before deciding whether to cut them off
* Autonomous engine revving at red lights
* Self-loathing cars
* Autonomous canyon jumping
* Cars capable of arguing about the trolley problem on facebook

{{comic discussion}}

1832: Photo Library Management

2017-05-05T07:28:34Z

162.158.90.174: /* Explanation */

{{comic
| number = 1832
| date = May 3, 2017
| title = Photo Library Management
| image = photo_library_management.png
| titletext = A good lifehack is to use messy and unstable systems to organize your photos. That way, every five years or so it becomes obsolete and/or collapses, and you have to open it up and pick only your favorite pictures to salvage.
}}

==Explanation==
{{incomplete|More explanation needed on what the comic is about, and the transcript is incomplete. The title text also needs to be explained.}}

The comic is split into 6 sectors as described below:
{| class="wikitable"
!Sector
!Caption
!Explanation
|-
| Left sector / Low Amount of Photos Taken, more than a little amount of time to sort
| No Problems
| With only a few photos to sort, and lots of time to do so, Randall is able to maintain his photo library efficiently.
|-
| Bottom sector / Area under line increasing where more time is spent as more photos are taken
| Can't find the good photos among the thousands of bad ones
| The amount of photos being taken is too high for Randall to adequately sort in the small amount of time he has.
|-
| Top sector / Area above line of negative gradient, as number of photos increases and time decreases
| Can't Sleep, Too busy sifting through photos to find the best ones
| Randall has taken too many photos, but has dedicated the time to sorting them. As a result, he is lacking sleep through his determination to complete the task.
|-
| Middle sector / Area in between both side lines, after No Problems but before cloud storage
| Photo library fits on most devices as long as they're not too old
| Randall takes quite a few photos, but still enough to fit on a more modern hard drive.
|-
| Middle-right sector / Area in between both side lines, after 'not too old' but before 'Moore's Law'
| Need cloud storage, external hard drives, or frequent upgrades
| Randall takes so many photos that he needs more storage than is on his computer to hold them.
|-
| Right sector / Area after 'cloud storage', going off until the two side lines meet
| Photo library grows faster than Moore's Law
| {{w|Moore's Law}} is a law that states that technology will keep getting better exponentially. However, Randall's photos take up so much space that even Moore's law can't catch up to the number of photos stored.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

A graph with the x axis being number of photos taken per day and y axis being the time spent going through photos per day, divided into six sections:

Section 1: Few photos taken per day, no limit to time spent: "No Problems"

Section 2: Some photos taken per day, a limited amount of time spent going through: "Photo Library Fits On Most Devices As Long As They're Not Too Old"

Section 3: More photos taken per day, less time spent going through: "Need Cloud Storage, External Hard Drive, Or Frequent Upgrades"

Section 4: A lot of photos taken per day, and even less time spent going through: "Photo Library Grows Faster Than [http://www.mooreslaw.org/ Moore's Law]."

Section 5: Above line increasing where more time is spent as more photos are taken: "Can't Find The Good Photos Among The Thousands Of Bad Ones"

Section 6: Below line of negative gradient, as number of photos increases and time decreases: "Can't Sleep, Too Busy Sifting Through Photos To Find The Best One"
{{comic discussion}}
[[Category:Line graphs]]