CC Design: Chrysler Studies Ergonomics in 1962, and Now Just Look!


Ergonomics, also called human factors, is the science of design and arrangement to maximise the efficiency, ease, and safety of people’s interaction with things. It was a young concept, as shown by this word/phrase frequency-of-use plot, in 1962…

…when a Chrysler man by the name of Betti wrote this paper, which you can have as an 8-page PDF by clicking this first page of it:

This new idea of ergonomics had been percolating amongst those charged with designing what we now call the HMI, the human-machine interface, or the UI, user interface: the controls and displays by which the driver interacts with the car. Controls are adapters to convert the needs and desires of the human operator to the behaviour of the machine, while displays are adapters to translate the needs and conditions of the machine into human-readable form.

The paper is nominally about instrument panels; around that time, Chrysler were paying a lot of attention to IP design. Shortly earlier they’d brought forth the whizzbang AstraDome, with its electroluminescent lighting—very effective, but complex, power-hungry, and expensive:

Greg Gjerdingen image on Flickr


 
The great big semicircular speedometer looks reasonably easy to read, but less so the other gauges; they’re kind of crowded together, one atop another. Maybe a little difficult to tell at a quick glance which one is trying to convey what message. And look: three same-size, same-shape sets of five same-size, same-shape pushbuttons—not such good ergonomics, maybe. Still, that electroluminescent lighting offered unusually good, clear legibility after dark, and that is good ergonomics.

Betti gives a wide-ranging analysis of the factors at play in IP design: short versus tall drivers’ view of the instruments through the steering wheel; distracting reflections of the lit gauges on the windshield at night; various ways of illuminating the displays; manufacturability, all of it. And it wasn’t just lip service; IPs like the ’62 Plymouth item at the top of this post were widely praised for their fast, easy, accurate legibility, though the gotta-just-gotta ’63 update marred it with a goofy typeface, much less readily legible and better suited to a box of kids’ cereal:

Other defacements, too; the ’62 separate fuel and temperature gauges were demolished and a crammed-together combo item crudely hacked into the middle of the panel; I imagine Mr. Betti and his engineering team were overruled by Marketing. Here’s that ’62 panel again, with the ’63 below for before/after comparison:

Some other models provided ’62 Plymouthlike generally sensible IP layout; others didn’t. The ’60-’61 Valiant panel, for example—nothing the matter with the big round speedometer, but the other three gauges were arranged like slices of pie in a same-size circle. Hiss! Wrong way to do it; it wrecks the consistency of indication. Instead of all gauges indicating “more” as they swing clockwise to point increasingly to the right, now the speedometer does that, but one gauge swings counterclockwise to the right for “more”, one gauge swings clockwise upward for “more”, and one swings anticlockwise upward for “more”. And that chrome faceplate is a glare monster—bad ergonomics:

I’m using Chrysler examples here because of my familiarity, and that’s where the paper came from, but everyone’s got their cheers and jeers for this or that control or display in whatever which make, model, and year of vehicle can be named…right?

(The ’62 Plymouth panel depicted twice in this post has been very craftily modified. See it?)

Now: my favourite part of this paper is nothing to do with how best to light the gauges, or the constraints of the “window” created by various-height drivers’ view angles through the steering wheel, or any of that. It’s about the expected direction of movement for controls, as illustrated in Figure 8 here, from page 4:

Everything in this diagram makes fine sense. But Betti uses one of my favourite examples to make a point about why it’s sometimes best to violate the convention:

An example of this is the instrument cluster lighting rheostat. The American motoring public has become accustomed to turning the rheostat control to the right to decrease rather than increase the lighting intensity. Any attempt to rectify this now would only create confusion.

True and correct: for decades, the IP illumination rheostat was built into the headlamp switch, which was almost always a push-pull-rotate design. The dashboard lights were dimmed by turning the headlight knob clockwise; brightened by turning it anticlockwise (and the dome light lit by turning it anticlockwise past maximum dash brightness, through a detent). That violates this convention…

…and this one…

Lloyd Alter image


 
…and, most relevant of all, this one…

…but it comports with this one! Why?:

Probably just easiest to build the switch that way in what, the 1930s or ’40s when the pull-push-turn light switch came in. I doubt if many people ever squawked that the nigh-on universal design of the car light switch involved turning a knob the “wrong” way to adjust the dashboard lights, unless they were water-powered. Probably very few people ever gave it a moment’s thought. That’s one thing about controls designed for good ergonomics: they don’t require much reckoning out. They might be intuitive because—as Betti describes—they’re designed such that they “ask” to be used the way they’re meant to be used, or (as in the light switch) they’ve been configured a certain way for so long that everybody’s got it in muscle-memory.

I don’t want to veer into a get-the-hell-offa-my-lawn-damn-kids territory of ranting that everything was better (it wasn’t) in the good (they weren’t) old days, but there’s a great deal of truth to that old advice about not fixing stuff that ain’t broke. GM disregarded that when they designed and promptly proliferated a completely new light switch: a split-rocker item introduced around 1985. Push one half of the rocker for the parking and tail lights, or the other half to add the headlamps, and turn a separate thumbwheel—the “right” way, now—to adjust the dashboard lights.

This wasn’t a terrible design; it worked okeh and wasn’t hard to figure out. But I don’t think it was any better than the previous pull-push-turn switch. At least not in any operational way; I’d bet a good dinner GM changed to this switch because it was 2¢ cheaper to make.

Other designs came from other parts of the world. European automakers used rotary-knob light switches—really just a reorientation of the pull knob: same three positions (off, park + tail lights, headlamps), just with a different operational motion, and still adhering to the overspanning principle: operate the control a little bit (first detent) to get a little result (small lights on); operate the control more in the same direction (second detent) to get a big result (headlamps on); return the control to its un-operated condition to turn everything off. Fine.

Japanese makers put the rotary switch on the end of the turn signal stalk. I personally don’t like this, but neither do I hate it overly much. I’m not a big fan of cramming a bunch of controls onto the turn signal stalk, but I save my fire and brimstone on the matter for GM (turn signals, wipers, screenwasher, cruise control, and I’m sure I’m leaving some out) and Ford (push the end of the turn signal stalk to honk the horn? Go drunk, Ford; you’re home).

Then there’s the question of how the driver should choose the headlight beam. A kickswitch on the floorpan was just about the only way it was done, at least in America, for a very long time. Not really good ergonomics, especially with a handshift transmission, though I guess there wasn’t all that much overlap between situations where you’d be shifting a lot of gears and those when you’d be switching a lot of beams. But still, with a kickswitch there was no easy way to flash the headlamps to signal other drivers. You had to grab the headlight switch and operate it on and off, or kick the switch a few times if the lights were already on. Migrating this control to the turn signal stalk was a terrific idea; much better ergonomics.

But just what should the driver do to select the beam? In many European cars, and for awhile virtually all American ones, you pulled the stalk rearward to flash the lights or switch between low and high beam. Whether the accompanying noise was a plasticky “SHTICKa!” from the switch itself at the top of the steering column in your Chev or Ford or Dodge or Jeep; or a muted “Clecka” from a bistable relay under the hood of your Volvo, that’s how the control was operated.

In Japanese cars, though, you pushed the stalk forward for high beam, pulled it rearward for low beam, and pulled it further rearward to flash the lights. I kind of hate that this has become the near-universal standard—again, probably because it’s cheaper to build what amounts to a toggle switch than it is to build one with a bistable latch mechanism. They work, but it’s way too easy to inadvertently knock the stalk into the high beam position and then drive around dazzling everyone else on the road with your high beams. And if that’s addressed by giving the switch a longer throw, then the stalk’s out of easy reach to operate its other modes (like, um, the turn signals) when the high beams are on.

If we apply the expected-direction-of-movement principle, the Japanese approach gets a better grade: you push forward to get more light, or pull back to get less light. So regardless of what the beancounters have decided, which way is better; more ergonomically correct: the one that’s not confusing because that’s how most of them work (pull/pull), or the one that’s not confusing because it follows the forward-for-more/back-for-less principle (push/pull)? They’re probably about equivalent, with comparable benefit and drawback lists. Having one design as the more-or-less standard is probably for the better; the previous mix of both meant we had to fumble and fiddlefutz with an unfamiliar car until muscle memory was retrained.

In the late 1960s there was interest in trying to bridge the gap between low beam (not enough seeing distance) and high beam (too much glare) with a “mid beam” or “turnpike beam”. The beam pattern itself was easily specified, and a variety of mid-beam lamps were designed and built, to good safety effect; eventually I’ll do an article about it. What sank the mid-beam was the unresolved question of how to control it: a three-detent push-push/pull-pull? A separate mid-beam on/off switch which would modify the behaviour of the regular high/low beam switch? Something else? Many were tried, but selecting from among three beams is a more complex task than simply toggling between two, and none of the control designs led drivers to reliably, quickly, and accurately select the intended beam.

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