Talk:2728: Lane Change Highway

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There's a section of the M25 motorway around London which does this... Never did like it. 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 Crowley Creates (and Destroys) The M25 - Good Omens. :-) --Kynde (talk) 08:25, 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. 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. 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-driver).
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). 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/ 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? --Kynde (talk) 08:17, 24 January 2023 (UTC)
Huh, didn't know that. Better safe than sorry! 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. —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. 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. 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) 172.69.68.66 14:41, 24 January 2023 (UTC)Bumpf

Yes, it was very late, after midnight EST. Barmar (talk) 14:56, 24 January 2023 (UTC)

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