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- Hacker News
- In my residential building we have two elevators, a big one and a small one, the small one can fit 3-4 people if they squeeze together, it can't fit a bicycle. And of course, they don't work independently, so if the small one is already on your floor the big one won't stop there, so if I have my bicycle with me, I need to send the small one to a higher floor first, and since people are using the lifts constantly, sometimes I need to wait for a while and repeat the same process. There were times where the small car came several times before I managed to stop the large one.by dsego
- Put the bicycle on its back-wheel, vertical?
- This is hilarious. But I'm also thinking: Maybe just use the stairs? Your bike suggests you aren't afraid of a little cardio.
- Slightly OT, but this reminded me of Colson Whitehead's _The Intuitionist_[1], an amazing speculative mystery novel about two dueling schools of elevator inspection philosophies: the Empiricists and the Intuitionists.by geephroh
- If you like elevator hacking don’t forget the seminal DEF CON talk by Deviant Ollam and Howard Payne: https://youtu.be/oHf1vD5_b5I
I watch it like once a year because it always tickles some part of me. Like all the different modes you can get an elevator into. The most fancy one people might encounter is when moving into or out of a building. The front office can give you a key to give exclusive control over an elevator so your movers aren’t waiting around on elevators. Put it in that mode and it will stop responding to calls from other floors. Only the person with the key can control the elevator. You get on, select the floor, door closes elevator goes, and then just chills there with the door open waiting for you. Annoying for the rest if the building (the building is down an elevator when in that mode) but is amazing for the person using it! But there are way, way more depending on the installation and function.
Fun fact: most elevator shafts are sealed at the top as tight as possible to prevent them from becoming a giant chimney in a fire. It never even occurred to me until I was in a mechanical room wondering “where is the hatch to look down the shaft?” The answer is “there is none, and it’s a feature not a bug.” You want to block all airflow so fire doesn’t chase up the shaft into neighboring floors. Who knew!
- Oh my god, every time I'm waiting for the elevator, I think of how annoying it must be to be someone who's building the algorithm to make sure that you minimize the amount of wait times between picking up people and taking them to their destination. Then I also wonder if the people who apply the logic and program the logic into the elevators are actually evil sadists that are doing it on purpose to make us wait longer enough and suffer a little extra.by orliesaurus
- One other thing to add: It isn't the elevator scheduling software being obtuse, that software gets a huge amount of thought. But elevators are expensive, and building owners do not over-spend on a whim. Typically, they have just enough cabs (if that) to handle the expected load.by dbcurtis
- They might have other objective functions like wear-and-tear on the elevators, total energy usage, or somethingby neutronicus
- I have done several third-party elevator integrations (software that talks to the elevator controller) for coordinating other equipment with the elevator. One thing that always struck me once I had full visibility into the location and motion of all the elevator cabs is how busily they are scheduled. Waiting in the elevator lobby for a cab seems to take forever, but viewed from the dispatch side, it is a flurry of activity and cabs are rarely idle during any hours the building is normally occupied. It is easy to nerd out just watching the status panel.
Another thing I learned: If an elevator mechanic says: "I'll meet you first thing in the morning." He means something like 4:00AM. They want to get in and out before people start arriving to start their day.
by dbcurtis - > minimize the amount of wait times between picking up people and taking them to their destination
I wish elevators accounted for load.
I've been to a couple of larger conferences where on the Monday morning after, the hotel elevator was just hammered. Everyone wanted to go down, and the elevator would dutifully stop on every single floor no matter how full it was. If you were mobility disabled on the 2nd floor, you were basically fucked if you had a flight to catch.
One would think that, if it's a 10 person elevator and it's already stopped on 10 floors requesting it, that it could save an extra 5 minutes by just going directly to the ground floor, instead of stopping on every floor with the same conversation of "Oof, can't fit in there. I'll get the next one!"
by StableAlkyne - Aside for the algorithms and how well they work, there is a psychological aspect to how people perceive "wait" times. It turns out just waiting is very annoying. But having people do anything during that same wait period → perceived as progress → not upset.
An example iirc was waiting for luggage at the airport. It takes min of x minutes for the first bags to show. In one version, passengers went directly from the gate to the luggage carousel and waited x mins for the first bag → unhappy. Then the airport decided to add a long, round-about "walk" path from the gate to the luggage area that burned some of those minutes → same total "wait" but happier passengers.
by psadri - I don't see how that's perception then? It was just made inefficient on purpose.
If I have to walk to the luggage area 10min and wait another 10min for my luggage it's not the same as if i walk 5min to the luggage area and wait 15min for my bag.
Yes, total time is the same but one scenario is acceptable because it feels inevitable and is under control (cannot personally move across space/time faster) the other is not because it feels like it could be improved (staff could unload bags faster).
by oliv__ - This story is shared all the time, but what airport actually did this? I’m not aware of any major US hub that meaningfully delays passenger egress like this.by ericpauley
- The biggest problem I always have with elevators is not the algorithm, it's the people seemingly being unable to grasp the concept of pressing either the up or the down request button, depending on where they want to go. Almost always I find someone will press both, because "then the elevator comes faster". Completely ignoring the fact that they end up going the wrong way first half the time, and adding an unnecessary halt for everyone already in there. How hard can it be to understand?..by olex
- I live in Ireland. 10+ years ago I used to the travel to the US quite a bit (5-10 trips a year). The majority of the time I would fly via a major EU hub like AMS or CDG even if there was a direct flight from Ireland.
The reason? Other factors that were important to me!
Examples:
- cost optimisation. I could fly business within company budget rules.
- flight time. I highly valued longer flight times between Europe and the US west coast so I got a proper night's sleep when flying east-bound. Doing connections on the east coast often meant quite short transatlantic flights that arrived very early in the morning. Much harder to manage the jetlag.
- Product offering. Some of the routes from AMS and CDG had much newer planes and cabins.
- Airline alliance loyalty. Given the travel pattern it meant sense to pick an alliance that delivered some value. Irish airlines didn't have much to offer and were much more expensive for a worse end to end product.
by donalhunt - I often enter it in the wrong direction.
Like let's say elevator is at 5, I am at 1 wanting to go to 3, and before I arrive there is already someone else at 1 wanting to go to -1.
I'll get in with them going DOWN so that it doesn't have to stop a 2nd time on the way up.
There are also other situations where I'll press it in the wrong direction if I think it's already likely to stop on the way down (due to me being on a popular floor) to save an extra stop on the way back up.
by qurren - In some places, I see people do that. It’s not stupidity. I learned the logical reason after observations. During busy hours in some busy buildings, there isn’t enough elevator capacity. Therefore, if you want to go down to the ground floor, taking a trip up and then down might be better (a less-bad worst case outcome, or even a better average outcome) than waiting for a non-full downward elevator. In such case, it’s logical to press both up and down.by gene91
- In situations like this the answer usually comes by flipping it and assuming they do understand, and asking why it makes sense now.
It's probably just the old 'fake loader' psychology, to be honest. Waiting without knowing when the elevator will arrive is boring/frustrating, where getting into an elevator that moves, even if the wrong direction, feels like progress.
Things are happening, and even if it takes longer ultimately that's a less frustrating state to be in.
by davnicwil - When you're at a lower floor and you're trying to go down, but its a time period where traffic is trying to leave you can end up in a situation where nearly every elevator going down is already full. So you call for down, cab arrives but is already full, it goes, you call again, another comes, its already full, rinse/repeat. Sometimes there's not much up traffic during that time, so it can be a legit strategy to just go ahead and call on the up and ride it all the way instead of waiting and hoping for space coming down.
Although I guess that's not quite what you're talking about.
by vel0city - And then when the elevator door opens, they ask the people inside: "Are you going up or down?" There's an arrow showing that, for Christ's sake.by trivo
- Yes, same here, in croatia people believe that you need to press the opposite direction to "summon" the elevator, if the elevator is on lower floor they will press the "up" arrow to bring it up to their floor. And then of course when the doors open they will ask "going up or down?", which is ridiculous. When I point out that the ground floor only has the "up" button they just ignore it (hard to unlearn ingrained beliefs).by dsego
- I don't think I've ever seen someone do that
- I am currently staying in an AirBnB of a 60 floor tower, and the three elevator shafts definitely cannot handle this (I don't think the building was designed with renting to tourists in mind). The elevators are frequently completely saturated during weekends, meaning that the elevator stops at each floor, but noone can get in because the elevator is already full. This means the backlog of people wanting to use the elevators is increasing until after rush hour, and I have at one time experienced a waiting time of over half an hour.
What I take from this is, elevators need a proper check to see if they are full, and if so skip floors.
by woeh - Or, the building / owners corp / code / city could simply ban short stay accommodation where it was never attended.
I would not want to be in that building if an evacuation alarm sounded.
- A 60 floor Airbnb tower? 2026 is wild.by cammikebrown
- > 60 floor tower, and the three elevator shafts
I don't think I've ever seen a 20-story building with less than 4 elevators at a minimum.
I've worked in low-rise office buildings with no less than 10 elevators.
Seems like that gross deficiency should have been stopped at the city inspector's office before plans were approved.
by pudgywalsh - I don't understand why the fact that it's an Airbnb really matters here? Unless a large number of apartments are meant to be empty, why does it matter if the tenant is short term or long term? Is it that short term users leave and enter their apartment more often?by ehsankia
- > I am currently staying in an AirBnB of a 60 floor tower.
ICE Condominiums Tower I, Toronto?[1]
> elevators need a proper check to see if they are full, and if so skip floors.
Elevator load measurement is an option you can buy.[2] Somebody didn't. 60 stories with three elevators is underserved, and needs all the control help it can get.
by Animats - Hah, I thought a lot about this problem while developing Sky Lobby, a mobile game (iOS / Android) about controlling and automating elevators.
In the game, some of the elevators are automated, and I wanted to choose an algorithm that best aligned with what players would expect an elevator to do. I ended up going with something close to LOOK, which (as the article states) is mostly what people expect. Except in case of ambiguity, I had it prioritise floors that have been waiting longer, to improve the p90, which is important in the game.
But now, add in these challenges:
- double-deck cabs (where attached cabs cover two floors at once)
- transfer floors between shafts
- express shafts
and the best (or at least, most expected) algorithm becomes much less obvious! I'll leave it as an exercise for the reader to figure out the best one.
Luckily I was in charge of a game, not a real elevator system, so I just had to find a heuristic that was good-enough, and could tweak the rules to let players manually override the elevator's plan if they don't like where it's going. This seems to have satisfied most players.
by hermanschaaf - Thanks for sharing this. I was just commenting about the challenge of making a fun elevator sim game. This looks great -- can't wait to play with it this weekend!by jamies