Category Archives: warnings

The Patient Writes the Prescription

jeep

I took the photo above in my brother-in-laws 2015 Jeep Grand Cherokee EcoDiesel. It says “Exhaust Filter Nearing Full Safely Drive at Highway Speeds to Remedy.”

I’d never seen anything like that before neither had he – it seemed like a terrible idea at first. What if the person couldn’t drive at highway speeds right then? Spending an unknown time driving at highway speeds wasting gas also seemed unpleasant. My brother-in-law said that he was having issues with the car before, but it wasn’t until the Jeep downloaded a software update that it displayed this message on the dashboard.

My own car will be 14 years old this year (nearing an age where it can get its own learner’s permit?), so I had to adjust to the idea of a car that updated itself. I was intrigued by the issue and looked around to see what other Jeep owners had to say.

I found another unhappy customer at the diesel Jeep forum:

At the dealer a very knowledgeable certified technician explained to me that the problem is that we had been making lots of short trips in town, idling at red lights, with the result that the oil viscosity was now out of spec and that the particulate exhaust filter was nearly full and needed an hour of 75 mph driving to get the temperature high enough to burn off the accumulated particulates. No person and no manual had ever ever mentioned that there is a big problem associated with city driving.

And further down the rabbit hole, I found it wasn’t just the diesel Jeep. This is from a Dodge Ram forum:

I have 10,000K on 2014 Dodge Ram Ecodiesel. Warning came on that exhaust filter 90% full. Safely drive at highway speeds to remedy. Took truck on highway & warning changed to exhaust system regeneration in process. Exhaust filter 90% full.
All warnings went away after 20 miles. What is this all about?

It looks like Jeep added a supplement to their owners manual in 2015 to explain the problem:

Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy — This message will be displayed on the Driver Information Display (DID) if the exhaust particulate filter reaches 80% of its maximum storage capacity. Under conditions of exclusive short duration and low speed driving cycles, your diesel engine and exhaust after-treatment system may never reach the conditions required to cleanse the filter to remove the trapped PM. If this occurs, the “Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy” message will be displayed in the DID. If this message is displayed, you will hear one chime to assist in alerting you of this condition. By simply driving your vehicle at highway speeds for up to 20 minutes, you can remedy the condition in the particulate filter system and allow your diesel engine and exhaust after-treatment system to cleanse the filter to remove the trapped PM and restore the system to normal operating condition.

But now that I’ve had time to think about it, I agree with the remedy. After all,my own car just has a ‘check engine’ light no matter what the issue. Twenty minutes on the highway is a lot easier than scheduling a trip to a mechanic.

What could be done better is the communication of the warning. It tells you what to do, and sort of why, but not how long you have to execute the action or the consequences of not acting. The manual contains a better explanation of why (although the 20 minutes there does not match the 60 minute estimate of at least one expert), not that many people read the manual. Also, the manual doesn’t match the message. The manual says you’ll receive a % full, but the message just said “nearly.” The dash display should direct the driver to more information in the manual. Or, with such a modern display, perhaps scroll to reveal more information (showing partial text, so the driver knows to scroll). Knowing the time to act is more critical, and maybe a % would do that since the driver can probably assume he or she can drive closer to 100% before taking action. It looks as though the driver needs to find a way to drive at highway speeds right now, but hopefully that is not the case. I can’t say for sure though, since neither the manual nor the display told me the answer.

Haikuman Factors

Sometimes it’s good to take a step back from the seriousness of our work and find new focus. H(aiku)man factors is the brainchild of my colleague Douglas Gillan. Each summarizes a concept in the field while following the haiku form of 5-7-5 and an emphasis on juxtoposition and inclusion of nature. Enjoy and contribute your own in the comments!

H(aik)uman Factors3

H(aik)uman Factors2

H(aik)uman Factors

H(aik)uman Factors6

H(aik)uman Factors5

H(aik)uman Factors4

All of the above are by Doug Gillan.

Other contributions:

Inattentional blindness by Allaire Welk
Unicycling clown
Challenging primary task
Did you notice it?

Affordances by Lawton Pybus
round, smooth ball is thrown
rolls, stops at the flat, wing-back
chair on which I sit

Escalation by Olga Zielinska
headache, blurred vision
do not explore Web MD
it’s not a tumor

Automatic Processing by Anne McLaughlin
end of the workday
finally get to go home
arugh, forgot groceries

Automation by Richard Pak
Siri, directions!
No wait, I’ll get it myself
Drat, I forgot how

Prospective Memory by Natalee Baldwin
I forgot the milk!
Prospective memory failed
Use a reminder

Working Memory by Will Leidheiser
copious knowledge.
how much can I remember?
many things at once.

Tylenol: A narrow margin of safety

I’m always surprised at how many people don’t know how dangerous Tylenol (or anything with acetaminophen/paracetamol) is. I can’t remember where I initally learned that just a few pills could cause liver failure, but it was at least 10 years ago. Of course, more than 10 years ago, I remember that Tylenol was the only painkiller allowed to be given out in my high school because it was so “safe.”

Anyway, it’s certainly been in the news lately and I have collected some interesting sources. First off, This American Life devoted an hour to investigating the problem, its history, and ongoing conflict. Absolutely worth a listen. Here is a teaser bit of the transcript:

Will Lee is one of the liver specialists and researchers who’s been calling attention to the dangers of acetaminophen. He is at the University of Texas Southwestern Medical Center and talked to reporter Sean Cole.

Will Lee: In one of the articles, we actually printed up the little coupon that I got with my Zocor prescription that says, $2 off on your next acetaminophen bottle. And one of the things on the coupon, it says safest. Not safer, or not safe, but safest. Well, this is the number-one drug killing Americans every year.

Sean Cole: Over-the-counter drug killing Americans.

Will Lee: Over-the-counter drug.

Sean Cole: Not the safest.

Will Lee: Not the safest, for sure. So I guess that’s– if you think I have a bee in my bonnet, that’s probably where it came from.

There are two human factors issues related to this “narrow margin of safety” that I’d like to highlight:

1. Warning design
2. Counter-intuitive doses for children

Warnings

If you’d like a good overview of warning design, see Wogalter, Conzola, & Smith-Jackson, 2002.

The warnings are printed in red on the lid of the container and say “Contain acetaminophen – Always read the label.”
warning
I know it took a long time to even have this, but I’d like to point out that this does not follow the best practices for warning design because it does not include the consequences or focus on the “hidden hazard.” Hidden hazards are really the reason warnings are important. Here are some examples:
  1. Does a knife need a warning that it is sharp? No, that’s not a hidden hazard. Now, if the knife is SO sharp it’s unexpectedly dangerous, then it needs a warning that conveys that information. I had a friend in high school who had a habit of testing knives with his fingertip. This never cuts you, just gives a feel for sharpness. Well, one time he had someone sharpen a swiss army knife for him – and what usually would have “felt sharp” went instantly through the skin down to the bone. That’s a hidden hazard.
  2. Does coffee need a warning that it’s hot? No, not if it’s just drink-ably hot. But yes if it is purposefully super-heated enough to cause 3rd degree burns. Watch this video to get new insight on the McDonald’s coffee story.

It is the narrow margin of safety that is the hidden hazard of acetaminophen. Nothing else available over the counter can kill you with such a small increase in dose. You can take 20x the recommended dose of Advil before it becomes threatening. I ignored the dosing for Advil once and took 6 in 3 hours rather than 2 – it made me sick and I regretted it, but would I deserve to die for that mistake? I could have died if it had been Tylenol instead of Advil. This hidden hazard is the most critical part of the warning – even if it’s on the label, I think it should be highlighted on the lid.

Which brings me to… the hidden hidden hazard that was created by the Tylenol company.

Counter-intuitive doses for children
In brief, for over a decade Tylenol provided medication labeled for infants and medication labeled for children (and of course, medication for adults). 99/100 people on the street would assume that these were in order of strength – least for the infants, more for the kids, and most for the adults. That assumption was correct for the kids and the adults. The counter-intuitive dose was for the infants: instead of being weaker because they were smaller, it was much higher. Their reasoning was that it is hard to get medication into an infant, so if it’s stronger you can get an effect with less. An article from Pro-Publica gives a more detailed summary.
An excerpt from Pro-Publica:

The two types of pediatric Tylenol had a counterintuitive difference. Drop for drop, the strength of Infants’ Tylenol far exceeded that of Children’s Tylenol.

In addition, the active ingredient in Tylenol, acetaminophen, has what the FDA deems a narrow margin of safety. The drug is generally safe at recommended doses, but the difference between the dose that helps and the dose that can cause serious harm is one of the smallest for any over-the-counter drug.

By confusing the pediatric products and administering too much of the infants’ version, parents could inadvertently overdose their children. Other manufacturers also made two children’s products with different concentrations of acetaminophen.

Between 2000 and 2009, the FDA received reports of 20 children dying from acetaminophen toxicity – a figure the agency said likely “significantly underestimates” the problem. Three deaths were tied directly to mix-ups involving the two pediatric medicines. Such errors may have caused some of the other deaths, but the agency has acknowledged that its data lacks sufficient detail to determine the precise cause.

This American Life included a heartbreaking case where parents were instructed to give their infant doses measured in terms of the children’s Tylenol (their doctor just said “Tylenol”), but since they had an infant they did what anyone would and used the Tylenol for infants, resulting in the death of their baby.

The big push seems to be for better warnings (with the example in the picture as “better.”) Indeed, this can have an impact – for example, as reported in the NY Times, removing infant versions of medication and saying a drug is “not for children under 2” reduced drug-related emergency room visits for that age range by half.

Excerpt from the NY Times article:

In 2007, amid mounting concern that infant cough and cold medicines were unsafe and misused, manufacturers voluntarily withdrew products intended for children younger than 2. The makers revised the labels on the rest of the medicines, which now warn parents that they should not be given to children younger than 4.

Government researchers said on Monday that those moves have had a remarkable effect: a significant decrease in emergency hospital visits by toddlers and infants with suspected medical problems after using these medicines.

Dr. Daniel Frattarelli, a former chairman of the committee on drugs at the American Academy of Pediatrics, praised the study, saying it showed that “the label is a very powerful tool for changing parent behavior.”

In the new study, published in the journal Pediatrics, researchers at the Centers for Disease Control and Prevention reviewed data from 63 hospitals to estimate the number of emergency visits from 2004 to 2011 by young children who had taken cough and cold medicines.

Children under 2 accounted for 4.1 percent of all emergency visits for suspected drug-related effects before the 2007 withdrawal, the researchers found, and accounted for 2.4 percent afterward.

However, even casual readers of the blog have probably noted how often I mention the Hierarchy of Safety: first try to design out the hazard, guard against the hazard, and warn. I’m not saying warnings aren’t important, but if we want to have the biggest impact we should be working on designing out or guarding against the hazard. Some ideas in that realm include bottle design that restricts the flow of liquid (this could prevent a child from dosing him or herself, but not parents from giving the wrong dose), and packaging “single servings” of medication, so that its obvious how much to give at one time. Although the treehugger in me isn’t a fan of more packaging, this also could provide more space for good warnings AND have those warnings in extremely close spatial and temporal proximity to use of the product.

 

Brilliant guard against accidents in indoor rock climbing

For those who don’t follow news of climbing accidents as closely as I do, there has been a spate of accidents associated with the automatic belay devices (autobelays) installed at climbing gyms.

These devices are handy to have around as they negate the need for a climbing partner, allowing one to exercise and train alone. The climber clips his or her harness into the device at the bottom of the wall, and it automatically retracts (like a seat belt) when you climb upward. At the top, you let go of the wall and the device lowers you slowly back to the ground. You are probably imagining that the accidents had to do with failures of the equipment – while that is not unheard of, the most recent issues have all been with climbers forgetting to clip into the system at all.

The most recent tragedy occurred this past September, where an experienced climber died after a fall in a Texas gym, and it’s been listed as so common it happens at “every gym,” though not always resulting in a fall. Here is the facebook page with members of another gym discussing a similar accident.

fb

If you talk with climbers or read accident forums you will invariably be faced with a large contingent bent on blaming the victim. I’ll grant that it is hard to imagine forgetting to clip into a safety device and climb 30 feet up a wall, but that’s because I hardly ever do it. One characteristics these accidents share is that the victims were experienced and used the auto-belays frequently.

When a procedure becomes automatic, it becomes more accurate and less effortful, but it also becomes less accessible to the conscious mind. When a step is skipped, but all other steps are unaffected, it’s especially hard to notice the skipped step in an automatic process. If caring more or working harder or “being more careful” could actually prevent this type of problem, we wouldn’t have any toddlers left in hot cars, perfectly good airplanes flown into the ground, or climbers falling because they didn’t clip into the autobelay.

That brings me to the device I saw installed at a climbing gym last night.

guardAbove: The guard in place, clipped to the wall and ready to go. Notice how it blocks the footholds of the climbs.

photo 2Above: Nikki shows how to unclip the guard before attaching to her harness.

 

photo 4Above: Clipped in and safely ready to go. Guard is on the ground and out of the way (it is ok to step on it!)

Let me tell you why I think this is brilliant.

  • It’s highly visible.
  • It functions as a guard. This adheres to the hierarchy of safety: First, try to design out the hazard. Second, guard against the hazard. Last, warn. These are in order of effectiveness. Prior to this device, I had only seen signs on the wall saying “Clip in!” (And a year ago, even those didn’t exist.) This device physically blocks the start of the climbing routes, demanding interaction before one starts climbing.
  • Using it properly does not add any additional time or mess to climbing a route. If it weren’t there, the climber would still have to unclip the autobelay from an anchor close to the ground, etc. With it there, the climber does the same thing and once done, the guard becomes a flat mat that doesn’t get in anyone’s way.

Is it perfect? No. You can also climb with a belayer on the same or nearby routes, and then it’s also blocking your way at the start of the climb. Some adaptation should be made by the route-setters at the gyms to minimize this. But overall, what a great and simple solution.

 

The Automobile Fuel Gauge – a ‘failed’ pictogram

Nice post over on Humans in Design on the semi-universal icon that tells you what side of the car to fill gasoline. It’s a little triangle that can go on either side of the icon, and the gas tank opens on that side of the car.

The post is called Lessons from a Failed Pictogram, and it covers the more common icon used on dashboards that is simply a picture of an old-timey gas pump with no triangle. This icon is simply an indicator that the gauge is for fuel – it doesn’t help the user know how to drive up to the pump.

The post addresses the myths that grew up about the fuel pump icon – that the pump handle indicated obtusely that the tank was on the opposing side. Of course, this would be a terrible indicator, but the take home message was that if users come up with imaginary meanings for a pictogram, designers should take notice. The users are begging for that message. From the post:

If a myth exists it’s often a search for meaning that can be used to identify a design problem, which is the first step to a solution.

Indeed, most of the pictures I found in an image search were just the pump with no indicator about the fuel tank. The one below stood out since it uses TWO icons.

On a personal note, I was almost 30 before anyone told me about the fuel indicator arrow.

 

Photo credit gmanviz @ Flickr

Photo credit Strupy @ Flickr

New automation will warn drivers of lane changes

Ford is introducing a system that first warns of a lane change, then actually changes the direction of the car if the warning is ignored. From the USA Today article:

When the system detects the car is approaching the edge of the lane without a turn signal activated, the lane marker in the icon turns yellow and the steering wheel vibrates to simulate driving over rumble strips. If the driver doesn’t respond and continues to drift, the lane icon turns red and EPAS will nudge the steering and the vehicle back toward the center of the lane. If the car continues to drift, the vibration is added again along with the nudge. The driver can overcome assistance and vibration at any time by turning the steering wheel, accelerating or braking.

Is this going to be as annoying as having Rich Pak’s phone beep every time I go over the speed limit (which is A LOT)? Just kidding – stopping a drifting car could be pretty great.

 

LOLcat photo credit to ClintCJL at Flickr.

What values are pilots allowed to enter for the weight of the plane?

I’d assume when pilots enter a weight estimate for the plane prior to takeoff that there would be a decision aid to prevents gross miscalculation. It certainly seems like an undue load (no pun intended) on the pilot to require entering multiple components for weight correctly. From the article linked below I am no longer sure how much automation is involved. Apparently, the pilot forgot to account for the weight of the fuel. Doesn’t it seem as though that would be the easiest weight to automatically enter?

From the article:

Pilot Miscalculates Plane Weight, Avoids Disaster

“The weight of the plane dictates the speed required to take off and too little speed could have caused pilots to lose control of the aircraft. Luckily, the captain realized something was wrong and compensated before the plane ran off the runway.

According to the report there have been “a significant number of reported incidents and several accidents resulting from errors in take-off performance calculations around the world in recent years.”

On a side note, I’ve been on small planes where we all had to be weighed as well as our luggage prior to boarding. If the margins are that thin, I sure hope no one made any data entry mistakes!

 

Photo credit martinhartland @ Flickr

Verdict Reached for Air France Rio Crash

The BBC has reported the incident analysis of the Air France crash that killed 228 people was due to lack of pilot skill in dealing with a high altitude stall.

Here is a link to the BEA Report from the Bureau d’Enquetes et d’Analyses. It’s a frightening read, as they give a moment by moment analysis of the last minutes in the cockpit. No emergency was ever noted and there did not appear to be any mechanical failures. It appeared that the flight crew thought events were under control the entire time (despite the alarms.)

 

 

Photo credit Vin Crosbie at Flickr.

Are we too trusting of GPS automation?

A GPS certainly makes life easier — and although I think many of us might consider what would happen if we were without it or it was unable to identify where we were, it is less often we consider how it may lead us astray.

One of our early postings on the Human Factors Blog was about a bus driver following GPS directions that led under a too-short bridge. His case was augmented by the fact that he had chosen the “bus” setting on the GPS and assumed any route produced was therefore safe for buses. The actual model of the GPS under the bus setting was only to add routes that only buses could take, such as HOV exits, rather than to limit any route.

NPR just posted stories of people in Death Valley who got lost from following GPS directions down roads that no longer existed. In one of the cases, their car got stuck for 5 days and resulted in the death of a child. After hearing numerous stories about inaccurate GPS directions from lost drivers, a ranger investigated the maps used by the GPS systems and found roads included in them that had been closed for years. How accurate and updated do GPS systems need to be to be considered safe? How can they address over-trust in potentially dangerous situations (e.g., death valley)?