How do you know if you are well suited to a career in information architecture?   Well, here’s a little test.  When you are finished reading this post, follow the link I provide to the US Department of Transportation’s Manual on Uniform Traffic Control Devices(MUTCD), which is the definitive, 864 page style guide for the country’s road signs, signals, and traffic markings.  If you soon find yourself delightfully lost in the visual minutiae and obscene specificity of the guidance provided, then you are either Rain Man or what I suspect is a natural born IA.

A new version of MUTCD was published December 16th, 2009 – the 10th edition in 74 years.   No document quite illustrates how design affects our daily lives and safety greater than this one does.  Most of the nuances of driving a car are deeply internalized by us drivers, so it’s not always obvious that the traffic experience is as designed as it actually is.  Take the shapes of regulatory signs, whose shifting geometry roughly correlates the number of sides of a sign to the intensity of the approaching danger ahead.  Stop signs (8 sides) are much sterner in their warning than diamond shaped Slow signs or triangular Yield signs. Circular signs, such as those at a rail-crossing, signal the most danger of all.  Afterall, the number of sides of a circle is infinite.  This dates back to a scheme created by the very first attempt to standardize signage in the early 1920’s.

Speed Hump is the correct term, but they offer the less hilarious "bump" option as well.

MUTCD takes careful consideration not to use traffic-planner jargon in such a way as to confuse drivers (or – let’s face it-make them laugh), even if comes at the expense of introducing misnomers and contradictions into their system of wayfinders.   Any leftish turn requiring a driver to initially make a right turn, such as those looping lefts on highway onramps, is called a “jughandle” turn by the pros, not a U-turn or a Left Turn, but the sign will say something like “U-Turn from Right Lane.”  A lesson to interaction designers – favor literalness over jargon in navigation.  A road-bump is actually technically a “hump,” but the sign says Bump anyways to avoid dangerous snickering by amused drivers.

Night speed limit signs are rendered in black with white characters - symbolizing "night" but sacrificing retro-reflectivity.

Information design, particularly color and iconography, is fussed over perhaps most of all.    Florescent yellow is the color of choice for most signs due to it’s high luminance and saturation – a combination that allows it to be seen in day, night, dawn, dusk and fog, with or without headlights.  The color yellow is also highly durable, meaning it takes longer to lose its’ color and retroreflectivity than other colors and making it a safe choice for a road sign’s design.  Curiously, the approved sign for showing night speed is an all black background with white characters – the black itself communicating “night-time” but making it less visible in the very time for which it is intended.

Purple is never used for lights or LED signs in traffic control even though it is high contrast.

Purple, it turns out, is also a very safe color due to it’s high contrast and saturation  – particularly Pantone^® Matching System^® (PMS) 259 (the exact color used by 13 states for E-Z Pass lanes).  Ever wonder why there are purple signs on those E-Z pass lanes but no purple lights or LED signs?  It’s because of a phenomenon called small-field tritanopia, which results in a “loss of sensitivity to blue light when the signal appears very small. As a result, a purple light might appear red with a blue haze surrounding the signal, potentially causing confusion that could result in erratic behavior as drivers approach toll booths.”  This is one reason why purple was not used much until recently as a road sign color, even though DOT has had it on it’s official “reserved” color list for decades.

Iconography is fussed over, but strangely optional.  Nearly every bit of icon bearing signage in the MUTCD offers up an icon-less alternative.   They seem to be saying, well if you’re an icon type go with this – but we understand some municipalities are just not into icons. Does that mean one is just not safer than the others?  Are there not studies proving that icons add important non-verbal cues and contribute to highway safety?

Use icons or don't use icons. What do we care?

Huh? The limitations of stand-alone imagery in road-signage.

And it’s interesting that traffic control designers face some of the same types of challenges that web designers do.  One central debate is clutter and the competition for that scarcest of all resources -even amongst drivers – attention.  Afterall, the MUTCD was started as a reaction to too many signs.  In the very early days of the automobile, local auto clubs used to put up signs and sometimes there would be 10 or 11 signs for a single popular road or attraction.

How many signs does it take? Well, enough to get the job done but not so many that drivers "consume" the safety benefit.

But how many signs is too many when it comes to public safety? Do signs cancel one another out like sidebar ads on a website?  It turns out that more road signs do not lead to greater safety, but not because drivers don’t notice them.  It has more to do with what an economist would call ‘consumption’ of the safety benefit provided by the extra signage.  If a driver is given a safety improvement, such as clearly marked lanes, signs, lights, etc. – she will “consume” the benefit and drive faster as a result.   So, guess what, it turns out traffic circles have less accidents than traffic signals – because drivers understand they are responsible for their own risk, shifting risk away from that of government.   It’s a paradox that web designers just don’t have to deal with.

Related Posts from Around the Web:

The Manual on Uniform Traffic Control Devices (MUTCD)

Distracting Miss Daizy – The Atlantic Magazine

The dashboard that monitors what the driver is doing, not the machine.

Ok, so I admit that I have a tendency to overvalue the impact of my own profession.  I believe Malcom McCullough when he says that interaction design is likely to be one of the great liberal arts of the 21st century.  The great American novel, when it finally arrives, will be planned in Omnigraffle.  And the fact that most of us deploy our tradecraft in the service of streamlining the movie rental process, selling sunglasses or laminate flooring, facilitating the sharing of snapshots and how-to articles on pumpkin carving does not diminish our greatness.  In fact, in my world, interaction designers are likely to be key players in all forms of meaningful societal change from here on in.   (Just try and tell me that Obama’s website wasn’t pivotal in his election!)  But what role does I.D. have in making the planet greener?  Even I struggled with that one.

For industrial designers, who work with physical products that consume materials both in their manufacture and their ongoing usage, the links to sustainable design principles are clear.  But for information product designers whose work is consumed primarily on screens, a claim to designing ’sustainably’ often feels like a stretch.  What is being conserved – pixels? CPU cycles? Yet recently I am learning that I need not feel that way.  It turns out there are many designers who leverage interactivity to directly make the world a more livable place – not only by raising awareness of sustainable principles but by directly affecting the way people use and think about their environment on a day-to-day basis.  On Nov. 12, while hosting a panel discussion on sustainability and interaction design for NYCUPA, I met Ted Booth – Director of Interaction Design at Smart Design.  Smart collaborated with IDEO in researching and designing the SmartGuage with EcoGuide for client, Ford – a true example of the unique power of interaction design to change human behavior.

The 2010 Ford Fusion is one of the first models to ship with the new SmartGuage desing in place.

The Ford SmartGuage with EcoGuide is an innovative instrument cluster (a reinterpreted automobile dashboard if you will)  for a new line of Ford hybrid cars.   IDEO did the user research, at the heart of which was an ethnographic look at the world of hybrid owners – including the cult-like “Hypermilers” who make a fetish out of squeezing every last drop of fuel efficiency out of their machines.  Smart did the design work itself.   The 2010 Ford Fusion is among the first models to hit the market with the new dashboard in place and immediately garnered considerable press and recognition for the novel philosophy behind it’s design (see further reading links at the end of this post.)   The  instrument panel design is purely digital, essentially one integrated monitor built into the car’s dash.   Being screen-based enables some interesting affordances that are perfect for a dual-engine automobile, for instance truly modal displays.   The tachometer toggles into “EV mode” when the electric motor is running, which makes sense given that electric motors don’t speak the language of “RPM’s,” and being modal allows the two gauges to share the same piece of real estate in the display.   The dash even has a tutorial mode that shows descriptive help text next to each type of instrumentation, seriously threatening the future existence of 10th grade drivers ed teachers.

A modal tachometer displays in typical RPM mode when the combustion engine is running, then toggles into a differently scaled "EV" mode when the electric motor is running.

What’s most profoundly innovative about the SmartGuage design is that it turns the traditional role of a car’s driver interface exactly on it’s head.  “A guiding principle was to give the driver feedback about their driving,” Booth told me in the pre-interview for our panel discussion.   “Up to now, car dashboards have communicated information about what the machine is doing, not the driver.”    The reason behind the shift in emphasis is a simple business problem.  Many hybrid purchasers, who are socio-politically predisposed to choosing such cars for their green benefits, are unhappy customers.  They just aren’t getting the increased fuel mileage they hoped for.  Some aren’t getting anything near the optimal mileage recorded by the test drivers and car reviewers.  It turns out a lot of this has to do with the way one drives a hybrid.

The Prius dashboard shows how much energy is recaptured by braking, but the display reinforces a misperception that braking harder is better.

How hard one brakes, for instance, is a key variable.    Hybrids, as many know, recharge their batteries through the principle of regenerative braking – a process of recapturing the kinetic energy generated by braking and storing it for later use rather than dissipating it in the form of heat.     The energy can be stored mechanically in the form of compressed air or a flywheel (as the high end KERS systems in Formula One racing cars do), or electrically in a capacitor or battery (as regular consumer hybrids do).  It is standard procedure in a hybrid dashboard to inform the driver about how much power has been regenerated.  But according to Booth, the existing instrument design gave drivers a mistaken perception about how to brake in order to maximize that number.  “Existing gauges show a spike of energy when a driver brakes,” he said, “which actually makes drivers think they should wait until the last minute to brake so they can brake harder and increase the amplitude of the spike.  In fact, it’s the opposite… slow steady braking delivers more of a charge, so we factored this into our design.”

It’s one thing to communicate to the driver a complex set of information about their driving and quite another to do that in a way that they can process – especially while trying to keep their eyes on the road!  The Smart design team did a couple of novel things here with the design.  The most famous is the use of a simple metaphor to give the driver an almost game-like sense of optimizing their driving performance – the “efficiency leaves.”    Initially worried that the leaves metaphor was going to be skewered by the car reviewers, it turned out to be exactly the opposite.

The hardest thing was to process all the inputs that affect fuel economy and feed them into a display in a way that a driver can process. We came up with the metaphor of leaves… drivers earn leaves as they conserve fuel. – Ted Booth, Smart Design

Smart Guage uses bold visual and information design to create highly "glanceable" instruments.

The team also focused on a bold, clear information design that embraced the limitation of “look-away” time – which implies that drivers have less then a second to safely take something in before returning their eyes to the road.   The fuel gauge, for instance, abandons the traditional needle design for a boldly rendered bar-graph that looks at first glance like amber liquid.   The leaves themselves represent an easily glanced at indication of driving success, but can be toggled into a more detailed mode showing feedback in the form of hard numbers.

Few examples better illustrate the centrality of the UX trade – and the potential opportunity to affect change for the better in places we never thought of- than this reinvention of the car dashboard.   These are heady, exciting times to be in the business of designing screens.

Further Reading:

Ford’s SmartGauge Improves Fuel Efficiency Through Better Instrument Design Fast Company