A June recall of Toyota's vehicles has sparked debate over how far engineers should go in designing for misuse of products. The recall urged Toyota to fix 154,000 vehicles to prevent problems that might occur when improper floor mats are used by owners. "The accelerator pedal can get stuck in the wide open position due to its being trapped by an unsecured or incompatible driver's floor mat," said a statement from the National Highway Traffic Safety Administration (NHTSA).
The latest recall, which involves the 2010 Lexus RX 350 and Lexus RX 450h, raises questions about the role of design engineers with its citing of "unsecured or incompatible floor mats." "Sometimes, owners use floor mats from another vehicle," Toyota spokesman Mike Michels told us. "Sometimes, they use aftermarket mats. We've even found carpet remnants stacked on the floor. The record was eight -- in that case, you couldn't even see the accelerator pedal."
The 2010 Lexus RX 350 was cited in a government recall related to floor mat problems. (Source: Toyota)
Use of unsecured floor mats can be a problem when they get caught on the accelerator pedal. It's not known if the mats caused any of Toyota's incidences of unintended acceleration that dominated the media two years ago. To prevent such problems in the future, however, Toyota has had to recall hundreds of thousands of vehicles. In some cases, the company's engineers re-shaped the bottom of the accelerator pedal to create more clearance. In others, they modified the plastic pad on the floor and even altered the vehicle floor pan to make more room.
Automotive experts told Design News that Toyota engineers might have been able to prevent the floor mat issues. Even though the mats may have been inappropriate for the Toyota and Lexus vehicles, they said, the problem involved interaction between just two components -- floor mat and pedal. As such, engineers probably could have imagined the potential failure modes, tested for them, and taken preventative measures.
"They should have been able to test for most of the conditions -- when the mats slide around, when they are mispositioned, when they are upside down, and even when the driver and passenger floor mats are swapped," Steven Eppinger, professor of engineering systems at Massachusetts Institute of Technology (MIT), said in an interview. "It's impossible to test for everything, but if you make your design more robust for the 50 things you can think of, then it's likely to be robust for the 20 things you didn't think of."
Although the number and severity of the owner complaints have not yet been made public, some observers believe that use of aftermarket floor mats by American consumers may have posed an unforeseen problem for Japanese designers. David Champion, senior director of Consumer Reports Automotive Test Center, told us:
They don't consider aftermarket floor mats, especially in Japan where everything is neat and tidy. There were also other issues -- like people putting rubber floor mats on top of existing floor mats. These are forms of misuse that can happen. And any misuse that would be considered normal in the US car market should have been taken into consideration.
It's hard to say if Toyota's engineers skimped over a key piece of the development process with this particular example and I'm certain there's no way an engineering team can be expected to anticipate every possible failure given the practicalities and constraints of development cycles. That said, this example points up the very key requirement to do some level of design for misuse as part of the iterative process. It's one of those areas like design for assembly and disassembly that likely gets short shrift in a lot of companies and across myriad industries--not just automotive.
I've seen a few graphs presenting the rate of complaints on Toyota "unintended acceleration before and after it hit the media.
Their rates appear to have been typical of the industry overall beofre the media circus. After...well of course a lot of people who just made a mistake saw a way for someone else to take the blame. And frankly in a panic situation very few people can accurately remember and assess what happened-it probably would not be tough to convince yourself it wasn't you.
IIRC the big splash case in the media, 4 dead in a Lexus ES, there were 3 floor mats stacked.
Just once, I'd like to see a judicial ruling tell the plaintive "YOU'RE AN IDIOT". As in, "You're an idiot for stacking 8 pieces of carpet remnant in the floor of your car. Your claim is rejected; case dismissed."
There is never going to be a hard line defining misuse. Putting another piece of carpet or a second mat on top of the first can probably be foreseen. But is adding a second and third foreseeable? Eight is not foreseeable. Where is the dividing line? It's going to be blurry for each and every design decision.
When will law require the user to take responsibility for his or her own actions? Can the engineer be expected to plan for an idiot stacking eight mats? Or even one that is too large for the footwell? Or one that is sized perfectly, but does not have friction nits on the bottom?
If this is the route society expects engineers to take to make a design "safe", then maybe engineers should require a 100-page consent document which describes the conditions for use of the product we design? Lawsuits can only proceed if you signed the document.
While I applaud Toyota for taking the step to announce this recall before an accident occurs, I can't help but wonder how necessary it actually is. If the floor mats in the cars are being made and installed correctly, why should they be responsible for the car owner's stupidity?
This is akin to the warning on the bottle of lemon dishwashing liquid - do not drink! Well, duh.
I think Bunter says it best. I'm skeptical too. It is impossible for designers and engineers to anticipate every way consumers will use or modify a product. This story, from the beginning, sounds more like user error. Not to add to the conspiracy theories here but there's more going on than we all know.
Bunter-Can you share a link with the graphs you mentioned. It sounds a lot like the research I've seen on alien encounters before and after the first Sci Fi movies. Interesting how there were no little green men until after Hollywood put a face on them.
Thanks for your kind words. Been a while since I saw those graphs, they were on some auto websites at the height of the hysteria.
I do remember that Toy had very similar incidents per xxx number of cars with Ford and GM. I also recall a long period graph of their UA complaints, little up a little down over many years, couple of humps and then it hit the news and it went up several orders of magnitude.
I recall my grandfather telling us, after he had ended up in the ditch on an icy road, how his car had accelerated after he hit the brakes. I remember even as a kid thinking that sounded wrong. Having since experienced loss of control on icy roads (Minnesota, duh) many times I realize that the sensation during the skid feels like things are happening very fast (Ooooooooooh noooooooo!).
Sensation is not physics. Nor can we replay the tape of the event and see that we really hit the gas pedal and ran into the hedge. So we believe that what we intended to do is what we did.
I think a short review of some of the absurd lawsuites that have won in court would explain this very well. There is no reasoning so stupid that some jury will not accept it.
I'm surprise Toyota would offer a recall for problems caused by owners. Wouldn't a letter to owners explaining that improper floor mats might cause problems be sufficient?
I fully agree with you, Rob, though I think it's a good business practice for Toyota to offer the recall to try to "fix" anticipated problems caused by owners.
A letter would seem to be the sensible thing to do, doesn't it Rob? Unfortunately, this is apparently a legal matter, which doesn't always have sensible criteria.
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