Basic Ergonomics of Safety by Merkel Weiss 7/1/11
One of the greatest joys of driving is that first moment that you snuggle into the seat and take up the controls. The firmness of the seat, the lateral support, the positioning of the wheel, instruments, and pedals all seem to conspire together in that instant to form a mental 3D topography of the ergonomic pleasure or displeasure of the car. It was not always understood in quite the way it is today, but ergonomic science is tasked with the public acceptance of interior design. Many a mediocre car has been successful in the marketplace as a result of sound ergonomic science, and the converse is also true. One good example of nice modern interior design is that of the Volkswagen/Audi. If you’re not familiar with it, I urge you to go sit in any modern VW/Audi car and quickly look around and take in the ambience. The execution brilliance is neither a matter of slathering of brightwork about the dashboard, nor the result of a multitude of neat arrays of buttons doing on-board fingernail grooming with fine adjustments for cuticle maintenance. The instrumentation of modern dashboard design has almost universally adopted the dual pot, single binnacle arrangement of all VWs since the earliest Rabbit or the Golf.
Despite the fact that cars have been marketed as seemingly being able to do more and more new, semi-useful tasks every year, this is not what ergonomic science is about either. In fact, I often wonder just how many new generation electronic functions are really a good idea. Example: there is a scarcity of modern drivers who take the time to turn off their headlights as a result of the fact that many modern cars do it for themselves. In the same vein, I read lately that cursive script (handwriting) is not a necessary skill with the advent of modern computers. You can guess that I disagree with this also. In a few short generations, you’ll find that graduates of modern schools won’t be able to write by hand, and it can only get worse as hand/eye coordination is a general requirement for most complex tasks.
The science of Ergonomics was popularized in the 1960s although it was formally present much earlier. A two-prong affair, the basis of which was the science of Anthropometry, Human Factors was initially applied to automobiles as an application of the size, scope, and movement patterns of people. The secondary branch was that of the psychology of motion, or put another way, the expectation of movement and resultant effects. In the 50’s we were treated to massive chrome dashes, the bigger the better. Fortunately, increases in understanding the nature of crashworthiness have saved countless people from having their bodies slammed into this unyielding bright metal array of glittery adornment, and many resultant concussions and broken bones. In the late 1960s, we all lamented the loss of flamboyant switches and binnacles with little fanfare for the injuries averted in the process. We then complained bitterly of the physically confining shoulder harnesses in the seats, never bothering to recognize the life saving qualities or the side bolsters limiting lateral motion developed simultaneously.
Most dashes and seats today are not as impact friendly as one might expect due to the manufacturers expectation that occupants will all use seat belts, and that the belts will restrain them from impact with the dash. As this may not necessarily be the case in many major impacts, most makers now provide a bewildering array of airbags beyond the dash mounted bags designed to restrain heads and necks from hyper-extending forward into the dash. Side bags protect us from striking door surfaces while head curtain bags are present to keep heads from impacting the upper window rail area. All of these bags are detonated through unique sensors. These sensors permit the dash bags to detonate only in a front crash, while the side bags are only active in a side impact. Additionally, seatbelt pretensioners are fitted to tighten the seatbelts around our bodies in the microseconds after impact but just prior to the expected movement of our bodies. Pretty fast, huh? You can thank Sodium Azide for that. That’s an explosive agent that is, at it’s heart, a genetic mutagenic agent. No need to complain about it; it’s the only explosive currently available that’s up to the task physically and fiscally.
Controls today are almost universally at optimal placement with near perfect operational feedback. In order to keep the cost and dash clutter under control, switches are often multifunction in layers of levels, mostly controlled by and related to some window function on a central screen. Here is where we depart from solid ergonomic practice. The manufacturers tell us that in a manner similar to the distraction of cell phone use, driver distraction is not a problem with hands-free use. They tell us that texting requires direct concentration on the keyboard and screen thus causing distraction, but that myriad of modern steering wheel controls do not. And yet, whenever you fire up the navigation system, you’ll most often find that you’ll have to agree with their lawyers before you can use the system. Well, what else can they say? The entire multi-function control system theory is based on the house-of-cards theorem that people can perform certain functions on the computer or telephone and not be distracted, while other activities tend to eat up more of our attention. This is a matter of degree that cuts the line awfully close, but it’s necessary if they are going to continue to supply the type and variation of controls that modern drivers expect. It’s the chicken or the egg question with a lot of sales at stake. I’m confident that at least another decade will elapse before we have solid information about the psychological requirements of various tasking states.
My neighbor has a late 90s BMW 3-Series which recently seized the engine. Why? She failed to watch the temperature gauge at a time when the thermostat stuck, overheated the thing and the resultant bill was pretty serious. I’m sure that this has happened before, perhaps even in epidemic numbers. Certain drivers just do not seem to be able to watch the car instruments and finally pull off just about the time that the whole thing goes nuclear. Modern electronics now have a handle on all of this and are likely to protect you from yourself by monitoring the engine temperature and refuse to permit the car to be driven so as to protect the engine from serious damage. But in this same regard, I wonder how the car is going to protect us from being distracted by the controls.
The fact that many are now open to voice command is one modern approach to mitigate the subjectively flimsy connection between the hands and the brain. I have a more simple-minded approach to the whole thing. I don’t answer the phone while driving. I’ll pull over first if it’s important. It’s not that I don’t comprehend the controls or that I feel distracted. I’m as used to multitasking as anyone. As a human being, I’m distracted by controls like talking on the phone, setting a radio station, or programming a destination into the navigation system. The time frame of each distraction need only be microseconds to miss seeing that Corolla that just made an unexpected left turn in front of you without noticing that you were on a collision course, armed with the theoretical right-of-way. Driving requires 100% concentration, especially in dense city environment. Even though the act of driving is shaded by the feel of the seat and the peripheral input from a myriad of controls, it’s often routine enough for us to be fooled into thinking that for this one moment, it’ll be OK to take your eyes off the road and set the digital temperature for the passenger side of the car….