2842: Inspiraling Roundabout

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Inspiraling Roundabout
Look, I just think we need to stop coddling those hedonistic roundabout hogs who get into the inner lane and circle for hours, wasting valuable capacity.
Title text: Look, I just think we need to stop coddling those hedonistic roundabout hogs who get into the inner lane and circle for hours, wasting valuable capacity.


This is the second consecutive comic that deals with confusing directions given to road users.

A roundabout, a form of traffic circle or rotary, is a traffic control device that serves as an alternative to stop signs, instead allowing for mere yields, as all traffic flows in the same counterclockwise direction around a central point (clockwise in left-hand traffic countries). Roundabouts improve safety and the flow of traffic, since they eliminate turns against traffic and full stops are only needed during high-traffic periods. One downside is that they take up more space than a traditional signaled intersection.

Various roundabout designs have been proposed and used throughout the world. Some use "out-spiraling" designs in which a driver wishing to access one of the furthest exits is initially directed into a lane towards the center, which then spirals outwards, guiding them out until they reach the intended exit. Randall, in contrast, proposes an "Inspiraling Roundabout" which spirals each entrance lane inward, eventually leading all three roads to meet in the center and become the exit lanes.

The caption states that it's "technically navigable", but that the Highway Department has vetoed it, presumably because of its deliberate complexity, impracticality, and the high risk of head-on collisions.

The system is fairly simple to use. Assuming left-hand driving / right-hand traffic, one could get to the next exit without entering the spiral. Getting to the subsequent exit would simply require making a lane change toward the right.

However, Randall is likely assuming drivers who don't change lanes, in which case his design would force drivers to travel ever deeper into the spiral, reach the center, and choose one of the other two lanes to attempt to exit the roundabout.

If vehicles don't change lanes, head-on collisions would be likely in a few scenarios, such as two vehicles reaching the center at the same time, or two vehicles trying to use the same lane going in different directions, one outspiraling from the center and one inspiraling from the entrance, eventually meeting each other head-on. (In this design, each inspiraling entrance lane can also be used as an outspiraling exit lane.)

The joke is that such a deliberately challenging and dangerous design would be unlikely to be approved.

The title text justifies this creative design by manufacturing an amusing problem of "coddling hedonistic roundabout hogs who get into the inner lane and circle for hours". Of course, it's unlikely (but not unheard of) that anyone would deliberately spend more time than necessary (let alone hours) circling a roundabout, so this design proposes to solve a non-issue. In reality, if someone finds themselves deeper into or longer in a roundabout that they need to be, it's more likely to be a misunderstanding of how roundabouts work and confusion about how to get out of them rather than a hedonistic "doing it for the thrill" rush.

  • In street racing culture, doing "donuts" -- circling a single spot at high speed to leave circular tread marks on the pavement -- is a popular pastime, but these drivers circle for a few rotations, not several hours.
  • The complaint of "coddling" some group was popularized by the title of the 2018 book, "The Coddling of the American Mind," a criticism of modern higher education.

Similar XKCD comics[edit]

  • 253: Highway Engineer Pranks also has a rotary that intentionally collides cars.
  • 2728: Lane Change Highway has a similar theme of changing lanes because the road is poorly designed -- and it was the first time Randall complained about his ideas getting rejected by traffic engineers.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[A large roundabout with three entrances of two lanes, three exits, and three spirals (as is CLEARLY evidenced by the three inner termini and three separate starts) of dotted lines starting from the medians between entry lanes and exit lanes of the same road which terminate in the center leaving a lane-sized median of plain asphalt.]
[Caption below the panel:]
Even though it was technically navigable, the highway department vetoed my inspiraling roundabout design.


  • Unlike inspiraling roundabouts, outspiraling roundabouts are a real thing, common across western Europe. They are known as "turbo roundabouts", though the design usually features at least 4 entrances/exits.

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First edit. I'm unfamiliar with the road rules in the comic so I just added the transcript in it's most basic form. OmniDoom (talk) 02:00, 17 October 2023 (UTC)

don't worry, even a wrong explanation is better than no explanation because it tricks people into being correct for you Me[citation needed] 03:15, 17 October 2023 (UTC)
New here, not sure of the procedure for discussing interpretation: I disagree with the interpretation that this is navigable by entering all the way into the center then driving out in a clockwise direction - that would be driving against traffic, which would be illegal and seem to violate the assertion that this is "technically navigable" (anything is "technically navigable" if you have a big enough vehicle and disregard for other people's property, but I'm assuming that we want to stay legal). I believe that the "correct way" to navigate this would be to signal and change to the right-lane until you get to your exit. The inward spiral may give cars a circuit or two to wait for a clear lane to the right, but the deeper you get, the faster you have to change lanes to get out again? --Candu (talk) 14:37, 17 October 2023 (UTC)
Dangerous, probably, but 'illegal' is kind of out the window here, since Randall has thrown all notions of sensible road design language out of the window. The lanes permit access to the other lanes at the centre, even if it's not a sensible move. 09:39, 18 October 2023 (UTC)
This IS Clockwise, look at the arrows. For some reason Randall drew a British roundabout. I assume because North America doesn't really have them but they're famously common in Britain? The thing is, driving clockwise each entering lane ends just at the next exit, meaning Randall conceived of this as a counter-clockwise spiral after all. NiceGuy1 (talk) 04:28, 29 October 2023 (UTC)
Those aren't directional arrows. They're an "exit line" marking (something similar to the actual UK Give Way markings?) or the equivalent US Yield sign (I don't see any indication as to what the US paints on its roads for them, but see the European version that is "shark's teeth"), as far as I can tell. You have two 'right-side driving' lanes entering into the spiralabout, from each direction, and one leaving it. (Part one of three sections by 17:57, 29 October 2023 (UTC))
You should sign your comments (I don't quite know how to post-sign a comment/fix it, so oh well). Such markings aren't used anywhere I've seen in North America, though. So North American drivers would understand them as directional arrows. :) Them being on-road Yield signs makes sense, but I have literally never seen that, only ever seen actual road signs for Yield - which is what I would expect if this was implemented, just that Randall can't draw an overhead version of THAT, :) Not in a way that we'd know what the sign said. NiceGuy1 (talk) 04:54, 19 November 2023 (UTC)
  • I did sign it. I wrote three paragraphs (excessive!?!), that was just the first...
  • What *I* do, to post-sign, is:
    1. Go into the edit-history/version comparison. Establish what was edited in without signing (if indeed it was unsgned, unlike how this one was),
    2. Copy the timestamp and ip (or username!) bit that applies,
    3. Go into (or back into the tab of) the page editor and add "{{unsigned ip||}}", or just "{{unsigned||}}" if it was a proper user at 'fault', and then shuffle in the IP(/username) between the two verticals and the timestamp after the second.
    4. ...or, if it's an established username that I know knows how to sign things (must have just forgotten), I copy something like "[[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:54, 19 November 2023 (UTC)" from a signed comment and paste in the correct username (three times!) and timestamp and consider it just my good deed for the day!
  • When researching the above response (and below, where I mention not being familiar with them), I didn't find much use of on-road markings, in the US, but they do exist. Not visually good enough pictures to link, as I recall, and maybe rare enough (perhaps nowhere you've been/noticed). I was most struck thst they looked most like European "dragon's teeth" markings than the British "honking big single elongated triangle" standard, but then I'm used to our (emminently sensible!) road-marking/signage being aittle bit adrift of what much of the (non-Commonwealth?) world seems to have decided is their standard.
    • e.g., the only "diamond" sign we have, in the UK, is a passing-place one; which actually depects a deliberate point-widening of the road, if you think about it. Though (probably for manufacturing reasons?) even that seems to have changed to be square-set. But none of these yellow-diamond-signs (except in the rear windows of school buses/coaches, the "children" warning, just like a "baby on board" vanity rear-screen 'hanger' that I'm sure makes people think twice before ramming the car in front(!)... 16:13, 19 November 2023 (UTC) (Part one of three sections, at this level.)
The confusing bit to me (not being familiar with US standard road-markings) is the dotted line acute 'elbow' where the (wrong-direction-)outspiraling hits the (right-direction-)outermost off-lane. It seems not to be a valid lane to enter (anticlockwise) but not be enough like the double-dashed 'give way line' that the UK uses (along with the Give Way 'inverted triangle' painted upon the road). (Part two of three sections by 17:57, 29 October 2023 (UTC))
Yeah, those lane endings should be solid lines, probably more. :) NiceGuy1 (talk) 04:54, 19 November 2023 (UTC)
In the UK, single dashes (of various lengths/gaps) have certain meanings, double-dashes (at a juntion) are a Give Way (together with the big 'yield' triangle, as noted) and solid lines are either Stop (in that context, but also with painted(+signed) STOP) or "do not cross".
e.g., central hashes (or chevrons, usually at junction merging/diverving) with a solid border indicate no driving into them (if you can help it), often leading up to central bollards, pedestrian-crossing islands and/or division of the road into dual-carriageway where you really do not want to be on/over the diagonal hashing.
But central hashes on the lead up to a right-turn (cross-traffic, that is) lane-split will have (long-)dashed boundaries, so that those intending to move into the un-hashed crossing-zone (where short dashed lines separate the new lane from the 'through lane', and again from the opposing through-lane that you'd implicitly Give Way to cross) can, where traffic flow and speeds make it more practical, use a short stretch of the hashed section (but not over the solid line on the side of the opposing lane!) to 'pre-enter' the tirning-meridian. Not, of course, to overtake traffic, going forward, and if anybody is signalling to merge over into the turn (but was not as hot to use the diagonally-hashed area) you'd be cheeky to not let them do so. (Or risk them not realising that you were coming up on their offside as they do decide to make that manouevre - *crunch*!) See Rule 130 for the short version... 16:13, 19 November 2023 (UTC) (Part two of three sections, this level)
So I reject the idea that Randall drew a clockwise/UK roundabout(-sort-of). It's still a US one, albeit weird for the reasons given (also, it's titled "Inspiraling Roundabout", not the "Outspiralling Roundabout" that the UK-version-of-Randall would hae had to call it, including spelling change). 17:57, 29 October 2023 (UTC) (Third and final part!)
Oh, the joke requires that this was intended as counter-clockwise, just pointing out the seeming arrows, :) NiceGuy1 (talk) 04:54, 19 November 2023 (UTC)
Well, 'arrowheads', maybe, but not road-arrows as I'd recognise them. This is just a sign, but does depict the style of arrow one might see painted to accenuate the awareness of which lane goes what direction. As this one, again maybe also depicted upon the road, warns that one is about to re-enter bidirectional traffic (from a multilane dual-carriageway or other one-way traffic system, usually).
But I find all the different approaches to these things interesting.
I've never actually driven abroad. (Technically... I've cycled in Europe. And drove in the Legoland 'Driving School' in Billund when I was a child (cycling in Denmark!) and that Legoland was the only Legoland in the world. And once had to be reminded that "You're not in England now..." by the 'instructor' over his loadspeaker who could see me and my Union Jack car-adornment had turned across over to the LHS of the mini road system... ;) )
But I've been a passenger in vehicles, in the US and EU, as well as walked along/across streets and lanes (leafy 'beyond-the-suburbs' ones in PA, for example, having no sidewalks so not really being sure if anyone in their right mind walked there, so perpetually ready to jump into the undergrowth if anything big/fast came rattling past, and possibly disobeying the US's unusually strong Jaywalking statutes at times).
And, of course, one gets to see the weird mirror-world and distinctly different signage in anything depicting 'foreign' roads (Hollywood on down), whether that's "right turn on red" signs in whatever city it happens to be in the US(/Canada?), or a "Warning: kangaroos" diamond alongside some Aussie outback highway or other.
Given the subtle state-by-state differences, I'm sure you'll know much more (from long exposure) about particular local peculiarities on the roads. Like how red traffic-lights tend to just suddenly appear out of nowhere (i.e. tree branches) if you're driving around Hazzard County, GA (or that their "Bridge Out" signs are considered merely advisary, if your vehicle is orange with a flag on its roof, but not if it is black-and-white with flashing lights atop).
Though I'm not really sure what I learnt about US Freeways from The Matrix Trilogy, I must admit. (Certainly nothing about being brief and to the point!) 16:13, 19 November 2023 (UTC) (Third and final bit of this awkwardly split reply-to-reply. To avoid more confusion than is inevitable.)

added longer explanation Me[citation needed] 03:05, 17 October 2023 (UTC)

Could we create a category for these "traffic" or "driving" related comics? This would include this comic and the previous, and others that relate to driving/cars/traffic. 04:02, 17 October 2023 (UTC)

in left lane driving countries this would work pretty well as a roundabout

... Except going clockwise (as the arrows indicate), each entering lane ends at the next exit. :) NiceGuy1 (talk) 04:28, 29 October 2023 (UTC)
See above, it's not going clockwise. 17:57, 29 October 2023 (UTC)

I've heard the Spanish and British road authorities are planing to implement this for roads going to France. 06:39, 17 October 2023 (UTC)

Actually, the correct solution is an out-spiraling roundabout, which if properly designed means that if you start in the correct lane, you end up at the correct exit without changing lanes. RIIW - Ponder it (talk) 07:37, 17 October 2023 (UTC)

Well if it spiralled the other way it would be a great roundabout design. 08:14, 17 October 2023 (UTC)

Out-spiraling roundabouts are getting more popular in the UK - they recently repainted the Wandsworth Bridge Roundabout as an out-spiral, and it's gone from one being one of the worst roundabouts in the area to one of the best. 10:04, 17 October 2023 (UTC)

An example I designed several years ago... :https://www.google.co.uk/maps/@51.5071913,-3.1457705,18z/data=!3m1!1e3 RIIW - Ponder it (talk) 19:34, 17 October 2023 (UTC)

About driving in circles for hours: https://www.youtube.com/watch?v=iAgX6qlJEMc --Itub (talk) 11:32, 17 October 2023 (UTC)

Uzumaki??? 12:24, 17 October 2023 (UTC)Bumpf

You're reading my mind! :) L-Space Traveler (talk) 00:44, 2 December 2023 (UTC)

I think the author of the explanation completely misunderstood the design. This is the turbo roundabout, except instead of getting everybody out it pulls everybody into the center, just like the highway supercollider from early xkcd. 12:29, 17 October 2023 (UTC)

Alternative ending/version - there is a singularity at the center of the roundabout Dllahr (talk) 12:42, 17 October 2023 (UTC)

I think the explanation as currently written is way overcomplicating the situation, it seems clear to me that this roundabout is designed (much like in the recent comic #2728), to require lane changes for some paths, and the inward spiral is simply to guide anyone that's indecisive or otherwise missing their exist out of the way of other drivers, and forcing them to make a decision rather than circling indefinitely to avoid a collision. The current description of having you go backwards out the spiral after reaching the end seems ridiculously over complicated and doesn't match any of the design elements of the path. PotatoGod (talk) 14:36, 17 October 2023 (UTC)

I agree. The broken lines indicate that lane changes are intended. 15:42, 17 October 2023 (UTC)

This design has a regulating effect on the traffic mass. (Assuming changing lanes is allowed.) When there is light traffic, cars can easily change on the next lane to reach their destination. When there is heavy traffic, some cars will fail to change lanes quickly enough, and they become trapped in the spiral. When the traffic becomes light again, the outermost cars will be able to leave the spiral. I estimate that up to 50 cars can be temporarily removed from the local traffic this way. -- 16:57, 17 October 2023 (UTC)

Should there be a category for this comic, 2728: Lane Change Highway, 253: Highway Engineer Pranks, and similar ones? -- 18:12, 17 October 2023 (UTC)

Why hasn't the next comic been added to explainXKCD yet? I thought a bot posted the comics on explainXKCD. 04:16, 19 October 2023 (UTC)

Magic Roundabouts[edit]

See these two "unusual" roundabouts in England



Actually, they are (no longer) roundabouts, but Ring Junctions. Effectively mini Ring Roads. RIIW - Ponder it (talk) 07:37, 17 October 2023 (UTC)

Yeah, I've never quite got the mystique of the "Magic Roundabout" - yes, it's kind of pretty and neat to look at, but in terms of usage, it's just a load of mini-roundabouts near each other. And "mini-roundabouts near each other" is just another name for "Britain's road network". Yorkshire Pudding (talk) 20:14, 19 October 2023 (UTC)
Swindon, I've heard of that place... I wonder if that's the "Roundabout of Roundabouts" I've seen pictures of... NiceGuy1 (talk) 04:33, 29 October 2023 (UTC)
Note that it's one of the four such ring junction Magic Roundabouts shown above, and I'm sure linked somewhere or other up and down this article. Yes, it's (in)famous enough, I'm sure you've heard of it. (Whether you've heard of Swindon, or not might depend upon whether you're a fan of Jasper Fforde, as much as anything else... :P ) 17:57, 29 October 2023 (UTC)

In France at least this design would not create any conundrum because roundabout rules are clearly stated and independent of ground markings. It could still be somewhat confusing. (talk) 10:43, 17 October 2023 (please sign your comments with ~~~~)

Pretty sure it isn't a reference to the Inspiral Carpets, but thought I should note them in passing... 22:17, 18 October 2023 (UTC)

The added link to the hours-long roundabout circling bicyclist is my first edit on this site, let me know if something should be done differently 04:40, 20 October 2023 (UTC)

Looks good, as it is. The sentence in which it is set could be slightly rewritten, perhaps, but that's just a personal reading (and not yet sure how I'd improve it) and doesn't make your workable markup addition at all wrong. 05:43, 20 October 2023 (UTC)

Uhhh, why did American Randall draw a British roundabout? Look at the arrow indicators, he has drivers driving on the left... I mean, sure, roundabouts are uncommon (almost non-existent in my experience) in North America and notoriously common in Britain, but still... Plus THAT way each entering lane ends at the next exit, meaning Randall meant it as right side driving spiral after all. ??? I feel like something should be said about how roundabouts take skill and experience to flow through smoothly, meaning that in areas where drivers aren't used to them they're actually more dangerous. I mean, imagine a driver who is used to 4-way stops having half a second to align and merge with cars flowing in from the circle? It takes SUCH instant decision making to align, at least with highway entrances you have the on ramp to assess the traffic you're joining to find your gap! My brother lives in a newer area where the local idiots just put in several roundabouts where there used to be straightforward 4-ways before, so I've seen the difference, the new way spikes the adrenaline and triggers anxiety (except, I guess, in people who have been using them every day and got used to them, and I have to think always SOME). To me, needing to get used to them makes them a bad idea. And it's WEIRD! Just 3 days ago I was introducing a new driver to those roundabouts near my brother! NiceGuy1 (talk) 04:28, 29 October 2023 (UTC)

(He didn't... see above. As you had to add multiple related statements in various places in this page, in more or less the same edit, I felt compelled to put a similar number of mostly related responses to them all, to not let anyone thinking you'd been left hanging.) 17:57, 29 October 2023 (UTC)