Article #2 Carrera UC7 “Bad foot work”

Picture of Adam Bahret
Adam Bahret
Screen Shot 2021 03 25 at 9.11.10 AM

“Amerikaner sind Idioten”

Part Two of the Carrera Use Case 7 series

More often than we think, customers who aren’t even trying to UC7 our products seem to end up doing so regardless.  That’s fine, it happens. However, it also tends to result in $1 billion + lawsuits that could have easily been avoided.

The big question is, who do YOU blame? I mean you, the person reading this article. When your team discovers a field failure root cause to be user error do you either:

  1. Investigate a way to minimize the likelihood of it happening again through design improvement or some other means?
  2. Mark the investigation as “bad customer” and move on?

It is surprising how often teams choose option “b” and simply put the fault at the customer’s feet. The mindset that drives this decision is that “someone has to be at fault and since we designed the product to specification, it’s definitely not us.”

Ok good for you, you’re in the right, you won’t get an “X” on your record.  But does that matter? The reason for root cause analysis is to improve product performance.  This translates into many beneficial results: increased market share, low warranty cost, plus not getting sued.

We’ll dig into this later, but first let me tell you about my latest finding in the Carrera UC7 initiative. Plain and simple, sports car pedals are spaced uncomfortably close for big boots. These pictures show a comparison of my feet at the pedals wearing my size boots and my regular sneakers. As uncomfortable as it may be, sports cars have their pedals placed very close together for a very important reason.  When you are driving with intensity, your feet are dancing on those pedals.  More importantly, you are actively using two pedals at the same time with the right foot;  this is called “heel-toe”.  Heel-toe is the technique of having your left foot on the clutch and your right foot on both the brake and gas pedal, so all three pedals can be controlled at the same time.  Yes, it is as hard as it sounds.  The ball of your foot is on the brake and your foot is turned sideways so the heel is on the gas pedal. This technique’s primary use is to correctly downshift when going into corners at the limits. As you are carefully braking to the threshold with the ball of your foot, you are simultaneously revving the engine up to the correct RPM with your heel. This is not a trivial task, the motor revving, because if done wrong spinning in 360s off the track when the clutch is let out is a common outcome. If the RPMs are too low, it’s the equivalent of pulling the emergency brake during a tight turn. Anything that assists with this maneuver, such as close pedals, is greatly appreciated.

Anyway, with my size 13 work boots, I found it hard to perform even the basics of regular driving.  For one thing, I was unaware that my boot was hanging over the brake when I thought I was on the gas and vise versa. This means that if I suddenly pressed on either I could get the opposite response, and I did, luckily in a small dose.

If I had the opportunity to report this “inconvenience” to Porsche, how should the designers address it? They could either dismiss it as a stupid American wearing big work boots in a sports car (go get in your truck you idiot), or investigate it and see if there is any way to mitigate. Because, although unlikely, the severity of this fault could end up being pretty serious.  In fact, this has happened and the outcome was bad.

In 1986, the TV program 60 Minutes did a piece called “Out of Control” covering the multiple accidents that had occurred with Audi 5000s in the US due to sudden acceleration. Drivers reported that the cars would, for no apparent reason, suddenly accelerate. These sudden accelerations resulted in six deaths and 700 accidents.  What followed the loss of an epic lawsuit for Audi was severe brand damage. Even  “severe”  would be considered an understatement.  Audi sales in the US plummeted from 74,061 in 1985 to 12,283 in 1991 and stayed that way for three more years. They didn’t get back to 74K/year in sales until 15 years later.

So, what was the root cause of all of this?  Audi placed the brake pedal and gas pedal closer than most other American manufacturers.  In their defense, they were a German performance car company;, Pedals being close together was the standard.  Their home audience, Europeans, all regularly drove manuals and were more spirited and focused on driving.  American drivers, however, hold a soda in one hand and a  cheeseburger in the other, steer with their knees, and don’t bother putting their feet on the pedals until something happens. Not taking these factors into consideration, Audi placed the brake and accelerator pedals in their automatic transmission models in a similar manner to a sports car.

Before the lawsuit and devastating brand damage, before the first Audi 5000 hit American shores, before six deaths, what do you think that design team would have said if you told them the brake and gas pedals are too close together for American drivers?  Probably something along the lines of “Who could possibly hit both pedals?” and “Well, if they do it’s their own fault for not being aware enough to have a foot cover a pedal at all times like you are supposed to.” Yeah, that was my guess too. 

So, this image of me with my big stupid boots in a tight sportscar’s footwell seems like the punchline for a “Guess how I banged up the Carerra in a parking lot” story.  But, here’s the thing:  As reliability and design engineers aren’t we supposed to look for the corner case?  To give an example, Toyota and Lexus went through a similar lawsuit-resulting miscalculation between 2002 and 2009.  In this case, it was root caused to the driver kicking over the all-weather mat and pressing it to the accelerator. As a result, Toyota paid $1.2 Billion as a criminal penalty and another $1.2 Billion as a settlement to its customers.  So, again, was there a moment in an FMEA around 1999 where someone asked, “Hey guys, what if the driver folds the weather mat over with their foot and it hits the accelerator?” and was dismissed with the response, “Not gonna happen Kevin, in that case why don’t we worry about what happens if they put a brick on the accelerator too. Next question.”

Maybe I’m the idiot for wearing big boots while driving a manual sports car, but maybe, in all actuality, that possibility is a good thing for automotive ergonomics engineers to talk about.

As a matter of fact, at some point in the design process, Toyota did identify there was a real possibility that a weather mat could get folded over and press on the accelerator. This was well documented.  At the end of the risk line item, they just chose not to address it because “customers should not fold over their floor mats” and “they are responsible to make sure all items are in place before driving.” 

How about your customers? Do you have any field issue root causes that you pinned on them?  Were those cases then neatly closed and filed away?  At the next design review or DFMEA, I implore you to dig up a few of them and bring them to the team.  Bring up the Audi and Toyota stories as well.  It makes a good case for spending a little time talking about how to mitigate how your customers might “incorrectly” use your products. 


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