Ideas for smarter elevators


in Daily updates, Geek stuff

O-train bridge, Ottawa

I am not sure if any elevator manufacturer has done so, but it seems to me that adding some sensors and algorithms could significantly improve the efficiency of the machines in tall buildings. It could be a very practical application of utilitarianism, aiming to reduce the average per-person journey time as much as possible.

For instance, if there are two elevators moving past a floor where someone has requested a stop, the one carrying fewer people could be assigned the pause, even if the fuller cabin would be there sooner. Similarly, if a number of people got on at once and only one additional floor was selected, the movement of that elevator to that floor could be prioritized, bypassing people waiting on other floors.

To implement this, all you would really need is weight sensors in the elevator floor (or a tension sensor on the cable) and perhaps thermal sensors in the waiting areas to identify how many people are awaiting an elevator on any particular floor.

Another good mechanism might be a panel on the ground floor – or any sky lobbies – where each person waiting indicates their destination floor. They could then be routed to a particular elevator. For example, if ten people are all waiting on floor 1 to go up to floor 40, an elevator might be assigned just for them, saving them the delay of a dozen stops up along the way.

One last idea is a phased return system following fire drills and other sorts of evacuation. Having random collections of people enter elevators ensures stops every few floors. It would be fastest to carry everyone who is going there to the second floor, then do the third, and move on up the building.

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{ 13 comments… read them below or add one }

Aggie March 22, 2008 at 11:09 am

You might be interested in some of the elevator work David Scrimshaw has done here.

Anon March 22, 2008 at 12:10 pm

Dollars to donuts says you came up with this stuff while stopping at floor after floor yourself.

. March 22, 2008 at 2:40 pm

Having random collections of people enter elevators ensures stops every few floors. It would be fastest to carry everyone who is going there to the second floor, then do the third, and move on up the building.

“If they were not bad enough at check-in, security and the boarding gate, when you get to the plane there’s more to come as passengers cram bags in lockers, maneuver kids or struggle into window seats.

But it need not be this way, says astrophysicist Jason Steffen, based at the Fermilab Center for Particle Astrophysics in Illinois. He has proved that airlines can make boarding times seven times faster by taking a more orderly — and scientific — approach.

The outcome requires passengers to line up in order, the first filling window seats and doing so in alternate rows. So from the back of a 40-row airplane, the first passenger fills 40A, the next 38A, then 36A. The next group then fills the window seats in between, so 39A, 37A and 35a. Once window seats are filled, passengers then go for the middle seats and finally aisle seats.”

John Hart April 9, 2008 at 12:07 pm

I have been an elevator inspector in London for the last 30 years, I am sorry to say on the new generation elevators(we call them lifts) this is already being used. The way it works is that when you arrive at the elevators on any floor, you enter the floor you want in the lobby area, not by pressing a button in the car. So on a bank of 6 lifts the computer knows exactly what each elevator is carrying , what floors it will be stopping at, where people want to go etc. This enables it to work out the most efficient way of transporting people within the building.

Dan April 9, 2008 at 12:49 pm

Yes, all of the major manufacturers offer what is called “Destination Dispatch” control systems for elevators. There are a few installations each in all the big cities so far. They are only used in high-rise buildings so far, and they are extremely expensive. We received an estimate to retrofit one of our elevators to test the new system and it cost more than the elevators did.

Milan April 9, 2008 at 2:28 pm

John and Dan,

Thanks a lot for the information. I am glad to hear that people have already put ideas like the ones above to use. I guess I just haven’t been in any buildings new enough to use them.

Next time I am in a city with lots of new skyscrapers, I will try to find one.

Why are these systems so much more expensive than conventional elevators (or lifts)? It would seem like systems that just incorporated weight sensors and a computer would only cost marginally more.

Milan April 9, 2008 at 2:30 pm

In case anyone else is wondering how elevator experts have found this post, it seems to be because of this blog post over at

Helmut April 9, 2008 at 8:56 pm

My compliments to the writer for the considerable thought put into elevator behaviour.
The conclusions have been realised by the elevator business, load weighing of elevator car content has been in existance for some time (Years) and the power of the computer (Microprocessor) has indeed been utilised to achieve the features mentioned in the article.
The outcomes have been fewer elevators for a given building populace. Should the modern systems be superimposed on an existing set of elevators the resultant would be a reduction in waiting times of at least 45 %.

. April 15, 2008 at 7:04 pm

April 21, 2008

This week in the magazine, Nick Paumgarten writes about the lives of elevators, and tells the story of Nicholas White, who was trapped in an elevator in New York City’s McGraw-Hill building for forty-one hours. Here is a condensed look at White’s ordeal, as captured by the building’s security cameras.

. April 15, 2008 at 7:19 pm

“In elevatoring, as in life, the essential variables are time and space. A well-elevatored building gets you up and down quickly, without giving up too much square footage to elevator banks. Especially with super-tall towers, the amount of core space that one must devote to elevators, in order to convey so many people so high, can make a building architecturally or economically infeasible. This limitation served to stunt the height of skyscrapers until, in 1973, the designers of the World Trade Center introduced the idea of sky lobbies. A sky lobby is like a transfer station: an express takes you there, and then you switch to a local. (As it happens, Fortune was working on a project to upgrade the Trade Center elevators when the towers were destroyed.)”

. April 15, 2008 at 7:21 pm

“You hear that interfloor traffic kills—something to mutter, perhaps, when a co-worker boards the elevator to travel one flight, especially if that co-worker is planning, at day’s end, to spend half an hour on a StairMaster. It’s also disastrous to have a cafeteria on anything but the ground floor, or one floor above or below it, accessible via escalator.”

. April 15, 2008 at 7:25 pm

“Smart elevators are strange elevators, because there is no control panel in the car; the elevator knows where you are going. People tend to find it unnerving to ride in an elevator with no buttons; they feel as if they had been kidnapped by a Bond villain. Helplessness may exacerbate claustrophobia. In the old system—board elevator, press button—you have an illusion of control; elevator manufacturers have sought to trick the passengers into thinking they’re driving the conveyance. In most elevators, at least in any built or installed since the early nineties, the door-close button doesn’t work. It is there mainly to make you think it works. (It does work if, say, a fireman needs to take control. But you need a key, and a fire, to do that.) Once you know this, it can be illuminating to watch people compulsively press the door-close button. That the door eventually closes reinforces their belief in the button’s power. It’s a little like prayer.”

. April 15, 2008 at 7:42 pm

“A vertical-transportation axiom states that if an elevator is in trouble the safest place to be is inside the elevator. This holds even if the elevator is not in trouble. Elevator surfing—riding on top of the cab, for kicks—is dangerous. This is why the escape hatch is always locked. By law, it’s bolted shut, from the outside. It’s there so that emergency personnel can get in, not so passengers can get out.”

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