Bad Ergonomics: Press GO to STOP

Bad Ergonomics: Press GO to STOP
[人因工程 ]
(2003/02/20)


Bad Ergonomics: Press GO to STOP

This example is taken from a European project called SAVE. Imagine that you drive a car that can take over control in case of an emergency, e.g., a cardiac arrest. To be sure, the system asks whether it should take over control, but it does so in a complex way.

Apart from being hardly audible, the text is difficult to understand. Literally the metallic voice says:

"It is supposed that you have severe problems to drive. If you do not want an activation of the autopilot, press the Confirm button."

Naturally a "Cancel" button should have been used, because that is what happens if the button is pressed: the action is cancelled.

Actually, I must say that the SAVE project is not bad at all. I worked on it, so how can I say bad things about it? But errors are made everywhere. I also believe that in the end this text was changed.

Editor's Comments:

The editor has cited numerous examples demonstrating why the term "ergonomic" must not be equated with "form-fitting" or "tactile". To do so debases the term. The sense of touch is one of the factors in Human Factors Design, but hardly the only factor, and often not the primary factor. The sense of sight is usually the first sense engaged in any Man Machine Interface, and as this example demonstrates, hearing runs a close second.

Let me be clear. The designers' less than perfect English grammar is not the problem. We are addressing design, and ergonomic defects transcend language. The problem is a failure to appreciate the life or death importance of clarity to industrial design.

The sentence "It is supposed that you have severe problems to drive", while awkward in its construction, is nevertheless understandable. This is not the problem. The problem is the second sentence, "If you do not want an activation of the autopilot, press the Confirm button."

Consider the way the choice is put to the user. "If you do not want an activation of the autopilot, press the Confirm button." The designer is saying "If you do not want something, confirm that you do not want it." Only not so clearly.

The product designer is demanding that the driver of a moving vehicle, possibly undergoing cardiac arrest, barreling down a public highway, to clear his head, unravel the designer's double negatives, then make a decision about whether or not to press a button, a decision which may or may not end his life.

The designer might as well ask the driver to play Russian Roulette with a double-barreled shotgun.

Obviously this has nothing whatsoever to do with foreign language skills, and everything to do with the fact that the product designer was not thinking clearly in any language.

How should the designer have worded the message? How about:

"If you can drive, press OK."

Wording the instruction in this direct and intuitive fashion is the linguistic equivalent of "natural mapping" in physical space. The positive state "can drive" is mapped to the positive affirmation, "OK". Positive is mapped to positive, just as when an electrical circuit is turned ON, the power switch reads "ON". This allows a user to understand his situation and react spontaneously, without hesitation or delay.

Other possibilities come to mind. The exact wording is not critical as long as the meaning is clear. The bottom line, as always, is "KISS". For those unfamiliar with the expression, it means "Keep It Simple, Stupid!"

-- Bevin Chu

Explanation: Bad Ergonomics: Press GO to STOP
Illustration: None
Author: Dick de Waard
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Nonergonomic! Long Live Analog!

Nonergonomic! Long Live Analog!
[人因工程 ]
(2003/02/20)




Long Live Analog!

The author/editor likes living in the Digital Age. On the whole, I prefer digital technology over older analog technology. I definitely prefer smaller, lighter, more durable DVDs to bulkier, heavier, easily damaged VHS video tapes. I even prefer audio CDs, warts and all, to easily scratched vinyl LPs. Audiophiles should admit that the problem with "gritty" or "harsh" sounding audio CDs is not that the music has been digitized, but that the digital "bits" are too coarse, because the recording industry set the bar too low when they established industry standards for the compact disc.

Digital data displays however, are another story altogether. For many purposes, analog dials are vastly superior to digital data displays. The reason should be obvious. Traditional circular analog dials communicate far more useful and important information than modern digital data displays consisting of a horizontal row of arabic numerals.

Many engineers and designers assume that the function of a clock or a speedometer is to provide the user with the time of day or the speed of the vehicle, and nothing more. They assume this bottom line data is all the information available and all the information worth communicating.

They could not be more mistaken. The traditional analog speedometer dial in the accompanying illustration doesn't merely inform the driver that he is standing still at the moment, it provides the driver with all sorts of additional, valuable information. Even with the engine turned off and the handbrake pulled, the traditional analog speedometer speaks to us, revealing the vehicle's theoretical maximum speed.

The general position of the needle on a large circular analog dial can easily be determined out of one's peripheral vision. Once a vehicle is in motion, the position of the speedometer needle along a 270 degree arc instantly informs a driver where his speed falls within the vehicle's "performance envelope". A race or rally driver can continuously refer to his analog speedometer and tachometer to time his gear changes, without ever taking his eyes off the twisting road ahead. Try that with a digital data display! Even the movement of the speedometer needle as it alternately swings clockwise and counterclockwise constantly updates a driver about his rate of acceleration and deceleration.

Now turn to the illustration of the digital speedometer. Contrast the poverty of information provided by a conventional numeric digital display. No comparison is possible.

Note: The terms "analog" and "digital" in this context refer only to how instruments display data, not how they process it. Therefore a PC clock that displays an old-fashioned circular clock face featuring hour, minute and second hands on a LCD monitor would be defined as "analog".

-- Bevin Chu

Explanation: Long Live Analog!
Illustration: Nonergonomic! Long Live Analog!
Author: Bevin Chu
Affiliation: CETRA Design Information Section
Source: http://www.philly.com/mld/philly/business/4814052.htm
Publication Date: 2003
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: The (In)Famous Palm Beach County Ballot

Bad Ergonomics: The (In)Famous Palm Beach County Ballot
[人因工程 ]
(2003/02/18)



Bad Ergonomics: The (In)Famous Palm Beach County Ballot

Submitted by Heino Widdel

Editor's Comments:

More proof that the term "ergonomic" must not be equated merely with design that is friendly to the touch. Far more is involved, in particular the sense of sight. Ergonomics is important. Unfortunately the general public seldom pays any attention to ergonomics until problems such as this create utter chaos. The Florida ballot fiasco was an object lesson in the importance of ergonomic design that should not be forgotten simply because election fever has passed.

-- Bevin Chu

Explanation: Bad Ergonomics: The (In)Famous Palm Beach County Ballot
Illustration: The (In)Famous Palm Beach County Ballot
Author: Heino Widdel
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: Keep Right

Bad Ergonomics: Keep Right
[人因工程 ]
(2003/02/17)



Bad Ergonomics: Keep Right

Thanks to John Rietveld, who has a large set of signs and signals on his homepage

http://signalfan.com/

Editor's Comments:

Normally this editor cannot resist the urge to editorialize at great length about the fundamental principles of bad ergonomics, but this sign has says it all!

-- Bevin Chu

Explanation: Bad Ergonomics: Right?
Illustration: Keep Right
Author: John Rietveld
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: Tonearm Control Lever

Bad Ergonomics: Tonearm Control Lever
[人因工程 ]
(2003/02/13)



Bad Ergonomics: Tonearm Control Lever

When the user of this poorly designed turntable lowers the tonearm control lever, tilting it down toward himself, the tonearm does exactly the opposite of what he has a right to expect, it rises up off the surface of the record!

Editor's Comments:

I have no doubt that the designer of this turntable was earnestly attempting to solve a difficult mechanical engineering problem to the best of his ability, and not indulging in mere product styling. I am sure he worked late into the night working out the complex geometry of the control lever linkage to the tonearm. Unfortunately he neglected the most important consideration of all. Mechanical engineering solutions are meant to be used by human beings, and human beings use mechanical devices certain ways and not others based on long experience with the world around them. It is not reasonable to expect human users to abruptly forsake these hard-won and usually correct instincts. Rather it is the responsibility of architects, urban planners, interior designers, and industrial designers to make sure the man-made environment conforms to the requirements of human physiology and psychology.

-- Bevin Chu

Explanation: Bad Ergonomics: Tonearm Control Lever
Illustration: Tonearm Control Lever
Author: Niels Taatgen
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: The Double Negative

Bad Ergonomics: The Double Negative
[人因工程 ]
(2003/02/13)



Bad Ergonomics: The Double Negative

In Czech 'Bez poplatku' means 'without toll'. The above sign indicates a toll road.

Editor's Comments:

If you were seeking proof that "ergonomics" is not just about "anatomically correct design", here it is. The "Man Machine Interface" includes all sorts of ways for humans to interact with human artifacts beyond the tactile. Gripping an automobile steering wheel is one way of interfacing with a machine, but hardly the only way. Merely reading the engine RPMs off an automobile tachometer also qualifies as interfacing with a machine. One need not actually touch a machine to interface with it. Therefore any defect that creates difficulty for users of technology qualifies as bad ergonomics, even a hard to read instrument gauge, even bad grammar on a road sign, such as a double negative.

Fiascoes like this occur when people in positions of authority forfeit their responsibilities. Clearly it was not a matter of cost. The only cost item here was paint for the letters on the sign. The text in the road sign read "Toll Free". The diagonal red slash painted across the text was some faceless bureaucrat's way of saying "NOT Toll Free". Apparently the mental effort needed to pause, clear his mind, and come to the realization the sign ought to simply read "TOLL ROAD" required too much initiative on his part.

-- Bevin Chu

Explanation: Bad Ergonomics: The Double Negative
Illustration: The Double Negative
Author: Dick de Waard
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: Stove Controls 2

Bad Ergonomics: Stove Controls 2
[人因工程 ]
(2003/02/13)



Bad Ergonomics: Stove Controls 2

On our holiday in the Alps we found this classical example in our rented house. Apparently they still exist, absolutely no clue is given which knob operates which heater. And only one light indicates that either heater is switched on.

My wife knew that as we read from left to right and from top down, the left hand knob had to operate the top heater, which was correct, but we frequently made a mistake. The best solution is to have the knobs arranged the same way the heaters are, two knobs below each other. If this is not possible for whatever reason, two indicators would be useful:

Although you could add a red surface on the right hand knob as to indicate that this one operates the heater with the red circle, you have to be aware that that circle becomes invisible as soon as you put a pan on it. Therefore, the cheapest solution is an engraved line to the heater.

Editor's Comments:

This set of stove controls represents essentially the same design problem cited in "Nonergonomic!: City Bus Door Controls". The problem here, as there, is the failure to clearly "map" control switches to the devices they control, be they bus doors or heating elements. Instead of being arrayed alongside and parallel to the heating elements, the control knobs have been relocated to the end of the stove, perpendicular to the heating elements.

This decision does not appear to have been arbitary. It was probably motivated by an entirely reasonable desire to position the controls close to the front of the kitchen counter. Nevertheless it was a mistake. The predictable result has been the loss of natural mapping, and the introduction of ambiguity, uncertainty and confusion. Imagine the cumulative frustration experienced by everyone who has ever had occasion to use this stove. Now multiply that by the number of units sold. I think you will agree that more alternatives should have been explored.

-- Bevin Chu

Explanation: Bad Ergonomics: Stove Controls 2
Illustration: Stove Controls 2
Author: Dick de Waard
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: Elevator Control Buttons

Bad Ergonomics: Elevator Control Buttons
[人因工程 ]
(2003/02/12)



Bad Ergonomics: Elevator Control Panel

This is the control panel of the lift (elevator) in our department. The first time you order a lift you'll definitely push on one of the top arrows. However, these arrows only indicate whether the lift is moving and in what direction. To order a lift you must use one of the lower buttons with the text "op" (up) or "neer" (down). Indicators and controls have exactly the same appearance here.

Editor's Comments:

Mention the word "ergonomic" and what comes to mind? If you're like most people, you immediately think of the countless "ergonomic" mice that "fit the hand" or "ergonomic" keyboards that look like they were sawed down the middle then glued back together at an angle. But in fact much of what makes an industrial product ergonomic or nonergonomic has little to do with what it feels like, and a lot to do with what it looks like.

Yes, the problem is that the UP and DOWN indicator lights were given the three dimensional shape of control buttons. But what makes the elevator control panel nonergonomic is not how these indicator lights FEEL, but rather how they LOOK. It is the LOOK that causes users to reach for the indicator lights instead of the control buttons. Its negative ergonomic characteristics impact the user long before the user's fingers touch the control panel.

The most misleading aspect of the look is of course the articulated grooves surrounding the arrow symbols. These grooves make the flush-mounted indicator lights look like control buttons that can be actuated by pushing on them.

A second possibly overlooked factor is graphic symbols are far more powerful than written text. Arrow symbols which POINT up or down speak louder than strings of text which spell out "up" or "down". Exceptions to this rule might be Egyptian hieroglyphs and Chinese pictograms, which are essentially ancient versions of internet browser icons.

Finally, the designer of this elevator control panel compounded his error by making the control buttons horizontal rectangles, while making the indicator lights vertical rectangles. The vertical axes of the indicator light rectangles only serve to strengthen the grossly misleading impression that the indicator lights are control buttons dedicated to controlling up and down movement. That the control buttons look as if they were squeezed in at the bottom of the panel as an afterthought, instead of occupying the favored central position on the control panel doesn't help either.

How might this design be improved for future production runs? One solution out of many would be to simply eliminate the two control buttons at the bottom of the panel, and redesign the indicator lights so that they are not just indicator lights, but also control buttons. The indicator lights already look like control buttons. Why not go ahead and actually make them control buttons, with indicator lights integrated into their surfaces?

-- Bevin Chu

Explanation: Bad Ergonomics: Elevator Control Panel
Illustration: Elevator Control Panel
Author: Werner Vogels
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Designs: How Do You Turn On the Shower? Example 2

Bad Designs: How Do You Turn On the Shower? Example 2
[人因工程 ]
(2003/02/11)




Bad Designs: How Do You Turn On the Shower? Example 2

This picture shows a shower head with with an on/off control. This is convenient, but together with the shower control below presents a potential problem. The problem is that both controls have to be turned on or the shower won't work. If either one or the other or both are turned off, the shower won't work. There really isn't any good way to tell which one needs to be turned on. Thus, there are three ways for the shower to fail to work and only one way for it to succeed!

Design Recommendations:

When you design a set of controls, try to minimize the number of ways for them to fail to work and maximize the number of ways for them to succeed.

Editor's Comments:

Products should be easy to use. As a fundamental principle products of any kind should work without having to wrack your brains figuring them out. They should be easy to make work, and hard to make fail. A product which meets this admittedly demanding criterion qualifies as a well-designed product. This applies not only to hardware; it applies to software as well. Some software exhibits the same "three ways to fail, one way to succeed" characteristic. It seems to have been written by computer programmers for other computer programmers, with the implicit attitude "If you can't figure it out, you're too stupid to be using a PC."

The truth is just the opposite. If first time visitors approaching a building can't tell which direction the lobby doors swing and which direction they're supposed to proceed to find the reception desk just by looking, then the architectural designer has failed, not the visitor. See "Bad Designs: Trapped between the Doors!" If first time software users can't install an operating system or an application straight out of the box and have it work at least passibly just by accepting the defaults, then the author of the software has failed, not the user.

The overwhelming majority of PC owners are not software engineers. That does not mean they are stupid. The overwhelming majority of PC owners' expertise lies elsewhere. If a computer programmer insists on treating PC owners who are not IT experts with contempt, he merely betrays his own lack of professionalism. He merely confesses an inability to perform his own job, which is to author programs that enable other specialists to perform their tasks more efficiently without diverting valuable time and energy configuring unfriendly software.

-- Bevin Chu

Explanation: Bad Designs: How Do You Turn On the Shower?
Illustration: How Do You Turn On the Shower?
Author: Michael J. Darnell
Affiliation: Bad Human Factors Designs
Source: www.baddesigns.com
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Designs: Lamp Switch

Bad Designs: Lamp Switch
[人因工程 ]
(2003/02/10)



Bad Designs: Lamp Switch

This picture shows the switch on our halogen desk lamp. It is a three-position rocker switch. Its three positions are

low (I)
off (O)
high (II)

To switch from low to high or vice versa, you have to move the switch through the off position. I wonder why it works likes this? Wouldn't it make more sense if its three positons were

off (O)
low (I)
high (II)

That way you wouldn't have to first turn it off to switch from low to high. It seems like a more natural order. One other problem with this design is that it is difficult to tell when the lamp is set to high vs. low because it turns completely off between the two settings.

Design Recommendations:

The order of the settings on a control should be natural. You shouldn't have to move a control into the "off" position to move it from one level to the next.

Editor's Comments:

Michael Darnell, author of www.baddesigns.com is right to challenge the above mentioned design. It is counter-intuitive in the extreme. "I wonder why it works like this?" he asks. We can hazard a guess. Almost certainly the designer of this badly conceived light switch thought to himself, "If I put the 'off' position in the middle, establishing that as a neutral point of departure, then users need only flick the switch one way to turn the lights to 'low', or the opposite way to turn the lights to 'high'. Think of all the wasted motion saved!" The only problem is, this sounds better in theory than it actually works in practice. Because of its counter-intuitive layout, far more wasted motion has surely been expended by baffled users clicking this switch back and forth repeatedly struggling to figure the switch out! Defective designs such as this wind up in production because designers are so enamored with the idea of how their designs ought to work, they don't bother to make sure that's how they actually work.

-- Bevin Chu

Explanation: Bad Designs: Lamp Switch
Illustration: Bad Designs: Lamp Switch
Author: Michael J. Darnell
Affiliation: Bad Human Factors Designs
Source: www.baddesigns.com
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Nonergonomic! Power Strip Placements

Nonergonomic! Power Strip Placements
[人因工程 ]
(2003/02/07)



Power Strip Placements

The author/editor has worked in a number of architectural design firms over the years, and he has noticed a strange anomaly. Many highly-paid design professionals are oblivious to some clearly nonergonomic aspects of their own working environment. The inconveniences are staring them straight in the face, but they just aren't seeing them.

Let me make make clear that this observation is nothing profound. On the contrary, the "design change" I'm prescribing is laughably mundane and costs nothing to implement. That makes widespread failure to implement it all the more inexplicable.

See the ordinary power strip in the illustration? No, I'm not about to criticize it for ergonomic defects. It's just your average inexpensive surge protected power strip, no better or worse than a dozen other similar products on the market. The question I want to ask is "Where have all the experienced design professionals I mentioned installed this product in their own offices?"

Ninety-nine out of a hundred have plopped their power strips on the floor beneath their desks, right beside the wall outlet, and each time they have to plug or unplug a device, they must crawl under their desks among the dustballs, getting their knees and palms covered with grit in the process.

To which one can only wonder, "Why?" After all, the typical power strip comes with a power cord several feet long, more than long enough to reach from the outlet to the average desktop. Why didn't they position their powerstrip on top of their desks, run the solitary cord down through the hole in their desktop to the wall outlet, then while seated in a comfortable, upright position, plug their electrical devices into this far more convenient row of outlets? Not only does this make it easier to plug and unplug devices when needed, it makes it much easier to shut off all the devices in a single motion by using the power strip's built-in power switch.

Why instead did they laboriously thread a half dozen power cords down through the same hole, until it was so clogged with wires any additional plugs would no longer fit through the opening?

The answer is: they were all trapped in a conceptual box of their own making. All these talented architects and designers subconsciously equated their power strips with those little cube taps which turn a single outlet into three, or four. As a result they locked themselves into the totally unwarranted assumption that wherever their wall outlets were located, that's where their power strip had to be.

Am I making a mountain out of a molehill? Many will think so. But no conscientious architect, interior designer, or industrial designer can dismiss my example as irrelevant. I bring this all up not to snipe at my esteemed colleagues, but to underscore a couple of sobering facts: one, even experienced design professionals whose responsibility it is to make our built environment as user friendly as possible, can miss the boat, and two, it is not as easy as we imagine to "think outside the box". First we have know we're in a box.

-- Bevin Chu

Explanation: Power Strip Placements
Illustration: Nonergonomic! Power Strip Placements
Author: Bevin Chu
Affiliation: CETRA Design Information Section
Source: www.baddesigns.com
Publication Date: 2003
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Designs: This is a Mop Sink

Bad Designs: This is a Mop Sink
[人因工程 ]
(2003/02/06)



Bad Designs: This is a Mop Sink

This is a Mop Sink

This picture is from a restaurant in Santa Barbara. The men's restroom contains no urinal. The fixture in the corner affords a certain activity. To try to discourage this activity someone taped a small sign to the wall above the fixture. The sign says "This is a mop sink."

Design Recommendations:

The mop sink looks enough like a urinal to use it as one. When simple things have signs, especially homemade signs, it is usually a signal that they aren't well-designed.

Editor's Comments:

In his landmark 1966 ideological manifesto, "Complexity and Contradiction in Architecture", architect and critic Robert Venturi ridiculed First and Second Generation Modernists for striving to make modern buildings communicate their inner functions entirely through their external forms, without recourse to symbols. Venturi insisted it was often far more reasonable to construct a simple container, i.e., a box, and to make no pretense about the fact that one was merely applying superficial decorations to the box after the fact. Not only was it economically more practical, it was philosophically more honest. Venturi had a point. It surely makes more sense to construct a neutral rectangular box and to tack an enormous illuminated plastic "Costco" sign on the front, than to resculpt the entire box at enormous expense, even distorting its structural system, merely to "express its function". Many modernists, second generation modernists in particular, committed serious errors quixotically striving after "functional expressionism". The above example however represents an exception. Here Venturi was wrong. Sometimes architectonic forms scream louder than signs. Sometimes the architect had better get the forms to tell users what's going on in no uncertain terms, because signs just aren't going to cut it.

-- Bevin Chu

Explanation: Bad Designs: This is a Mop Sink
Illustration: This is a Mop Sink
Author: Michael J. Darnell
Affiliation: Bad Human Factors Designs
Source: www.baddesign.com
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect

Nonergonomic! City Bus Door Controls

Nonergonomic! City Bus Door Controls
[人因工程 ]
(2003/02/06)

City Bus Door Controls

The author/editor works in Taipei and takes the bus to work every day. One feature of the buses that has caught his attention is the design and layout of the bus door opening and closing controls. The controls consist of two levers which move up and down that are mounted side-by-side on the dashboard, slightly to the right of the steering column.

The general location of the two levers, though not ideal, is acceptable, and within reach of the driver's right hand. The problem is not with the general location, but with the size of the levers, their orientation, and their direction of travel.

Design Recommendations:

The levers are far too short. I am guessing here, but they appear to be about 2 inches or 5 centimeters in length. However long they actually are, they should be much longer -- two or three times as long. How do I know this? Because every bus driver in Taipei, without exception, has jerry-rigged his own custom remedy. Most have cut 4 to 6 inch lengths of rubber hose and slipped them over the black plastic switch extensions. The rubber hose extensions work suprisingly well. Not only do they allow the driver to flick the lever more easily, they provide a friendlier Man Machine Interface, cushioning the impact on the driver's fingertips. Some drivers have deliberately cut one hose shorter than the other to distinguish the front door switch from the rear door switch. These ingenious bus drivers who used their heads ought to change places with the product designers. Others have removed the black plastic switch extensions altogether and replaced them with what I swear are plastic ballpoint pen housings. They look like Bics.

The levers are oriented incorrectly. They should not be oriented one beside the other, but rather one in front of the other. Why? Because the doors to the bus are oriented in one in front of the other, therefore the door controls should naturally map this "one in front of the other" arrangement.

The levers move in the wrong direction. The levers should move left to right, not front to back. Why? Because when the doors open they open left to right (toward the curb), and when they close, they close right to left (toward the bus body shell). Therefore the movement of the levers should naturally map this "left to right, followed by right to left" movement. With switches arranged in this fashion, the driver who wishes to close both doors need only open his palm and sweep the two levers inward toward his own body. This movement does not require pausing to recall some artificial, consciously memorized "mental rule" before executing. Being completely natural, it feels right and is easily performed spontaneously, without the need to second guess oneself. That is what good design is all about.

The levers should not be the same length. The top or front door lever should be made longer than the bottom or rear door lever. The driver can then close either door or both doors in a single motion, merely by positioning his hand higher or lower before he flicks the levers left or right.

The bus manufacturers should pay attention to what end users, i.e., bus drivers, are telling them, indirectly. Bus drivers on Taiwan have been making these spontaneous modifications for at least ten years -- I first witnessed this Do It Yourself modification back in 1992. So why hasn't anyone with the bus manufacturing companies done anything about it in all this time? As is often the case, problems such as this persist not as a result of scientific and technological limitations, but as a result of defects in human institutions.

Explanation: City Bus Door Controls
Illustration: City Bus Door Controls (to be added when available)
Author: Bevin Chu
Affiliation: CETRA Design Information Section
Source: Bevin Chu
Publication Date: 2003
Original Language: English
Editor: Bevin Chu, Registered Architect

Bad Ergonomics: Ship Thruster Controls

Bad Ergonomics: Ship Thruster Controls
[人因工程 ]
(2003/02/14)



Bad Ergonomics: Ship Thruster Controls

This picture was taken on the bridge of a Danish vessel. Visible are: two control levers, two meters, 2 times two indicator lights (yellow and blue) and 2 times two control buttons (black and red). Notice how the red buttons have been covered with tiny plastic cups usually used to dispense liquid medicine?

Pushing a black button permits the officer on watch to assume control of the ship's thrusters. Pushing a red button on the other hand initiates a full emergency stop. The only difference between the two buttons with radically different functions, is their color. When an officer on watch uses the thrusters alongside a quay, he must turn his back to the control panel and look out the front window. Needless to say it is very difficult to distinguish the color of the buttons with ones back to the panel. Incidents have occurred in which the officer on watch inadvertently pressed the wrong button causing a full emergency stop just when he needed power from the thrusters. To prevent this potentially catastrophic mistake from happening again, the crew placed cups over the emergency stop buttons.

Editor's Comments:

In "Nonergonomic!: City Bus Door Controls" this editor cited an example of nonergonomic design that has caused bus drivers on Taiwan no little frustration, and which could conceivably lead to passenger injuries. It is not hard to imagine a passenger getting caught in one door because the driver momentarily became confused and thought he was closing the other door. But the downside risks of the bus door control defect pale next to this example.

-- Bevin Chu

Explanation: Bad Ergonomics: Ship Thruster Controls
Illustration: Ship Thruster Controls
Author: Thomas Koester
Affiliation: Human Factors and Ergonomics Society Europe Chapter
Source: http://utopia.ision.nl/users/hfesec/index.htm
Publication Date: 1998-1999
Original Language: English
Editor: Bevin Chu, Registered Architect