Unintended Acceleration In Toyotas: The Ghost In The Data

Edward Niedermeyer
by Edward Niedermeyer
unintended acceleration in toyotas the ghost in the data

We didn’t make it down to the first meeting of the NHTSA-National Research Council panel tasked with studying unintended acceleration, but apparently we weren’t the only ones. A scan of the MSM confirms that a number of “more study is needed” stories were filed for the occasion, a good two weeks ago now, but we’ve been pointed towards the presentations for that meeting [ available for download here, all 128 slides in PDF format here], and we feel comfortable drawing a few conclusions from them. In fact, we’d even argue that this data puts a lot of the controversy over unintended acceleration in Toyotas to rest.

As the slide above indicates, there have always been three possible outcomes to the hunt for a ghostly electronic problem with Toyota’s throttle control units: either there’s a problem, there’s not a problem, or there’s a weakness that can be learned from. Remember, NHTSA has already fined Toyota for a slow recall of sticky pedals… for this study, we’re looking at instances of electronic issues. So, have NHTSA and the NRC found anything that indicates any kind of problem?

On the face of it, they have. Looking at the Vehicle Owner Questionnaire reports filed in the NHTSA database, it’s clear that complaints of sudden unintended acceleration in Toyotas have increased massively since 2008. But one slide alone doesn’t tell the whole story… first we must look at how this data came about.

Starting with 426,911 complaints since 2000, NHTSA eventually narrowed down to UA complaints only, finding nearly 20k incidents, which were winnowed down by “manual review” to about 11,500 complaints. How thorough this “manual review” was is a crucial issue though, because Bertel has pointed out that NHTSA’s database counts a number of cases as “UA-related” even when the circumstances don’t seem to fit the diagnosis. Still, even assuming the data are all relatively kosher, you’re left with Toyota causing about 3,000 of the 11,500 cases of unintended acceleration. This is the first sign that the 2009-2010 data is being skewed.

Another way to look at the data: incidents per 100k units. Already we can see weakness in the claim that Toyotas are uniquely affected by some kind of mysterious problem: Volvo, a company built on its reputation for safety, has had nearly an identical rate of UA complaints per 100k vehicles.

After NHTSA and the NRC “manually reviewed” the complaints (theoretically winnowing out fraudulent claims), Toyota starts looking even better by comparison. Before October of 2009, Toyota’s UA complaints were on-par with GM and Chrysler, and actually lagged behind Ford. Only post October 2009, when the media-fueled scandal started to take off, did Toyota’s UA complaints start getting out of hand. So, what can we conclude from this?

Yes, even NHTSA admits that there’s a “publicity effect” going into the spike in Toyota UA complaints. Given that the rest of the data fail to provide a pattern of UA problems in Toyotas, media and lawyer frenzy are the only plausible explanations for the recent spike in complaints. But we’re not done yet… next, let’s look at these incidents and try to find out what’s going on.

This might just be the most significant slide in the entire string of presentations, as it proves that the overwhelming majority of Toyota UA complaints took place at low speeds (another slide shows that the majority took place in parking lots). Note that these are not the high-speed freeway terror events that the media so blithely latched onto at the height of the frenzy. The fact that nearly all of these complaints happened at low speed is yet another parallel to the Audi 5000 debacle.

Another major factor: age. Extremely young and extremely old drivers are far more likely to experience sudden unintended acceleration… on this basis alone, it should seem clear that driver error is a major factor in most UA cases. Taken with the fact that the majority of these cases took place at low speeds, in parking lots, and that most complaints have been filed since the scandal broke, and the picture becomes fairly clear: the recall has given a green light to complain about any kind of accident that involves a Toyota that is unable to stop. What any car could do that would make it impossible control under 15 miles per hour is difficult to imagine.

This having been said, if you break the data down to incidents involving Toyota Camrys, you do get some interesting results. The fifth-generation Camry’s rates are far lower than the sixth-generation, which is a difficult statistic to square with the publicity effect hypothesis… especially because this graph shows only data for pre-recall complaints.

Finally, the only other correlation to be made from the NHTSA-NRC data is that electronic throttle control does play into the rate of complaints, although because this graph is not weighted for the publicity effect, it’s far from conclusive.

The upshot? Flawed as it is from the get-go (due to its amplification of the publicity effect), the NHTSA VOQ data shows few patterns that indicate an underlying problem unique to Toyota vehicles. Within the subset of Toyota UA complaints, there are patterns pointing to electronic throttles and the Mk.VI Camry, but these (though intriguing) do not explain why complaints of UA in Toyotas have taken off in the last nine months. In fact, the data more broadly suggests that Toyota is one of several manufacturers with elevated levels of UA incidents, and most of those incidents occur in situations where nothing prevents full control of the vehicle and where “accidents” are generally higher.

NHTSA and the NRC should continue to look into UA, and should continue to look into the possible causes for elevated complaint levels about Toyota, Ford, GM, Chrysler and Volvo cars, but the search for a “ghost in the machine” that uniquely affects Toyota products is clearly headed nowhere fast. Don’t expect outcome #1 from the top slide to come about, and even coming up with something conclusive for an outcome #3 seems unlikely.

In his presentation on human factors in UA [in PDF here], Richard Compton, Director of the Office of Behavioral Safety Research estimates that there are 10b “opportunities” for pedal misapplication each day, and he cites research showing that “correcting” pedal misapplication usually makes the situation even worse. His conclusions?

This, in a nutshell, is what the whole Toyota unintended acceleration scandal is boiling down to: either pedal design or some other ergonomic issue makes UA more common, in which case the government can regulate it, or Americans are really becoming worse drivers and are always glad to have a convenient scapegoat for their ineptitude. As unsatisfying as these conclusions are, making peace with them is the only healthy choice at this point. Unless, of course, Government-run “behavioral training and adjustment” sounds like a practical solution to you.

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3 of 38 comments
  • Tachyon Tachyon on Nov 15, 2010

    More dead Camry drivers in Utah-- And, they'd even had their pedals and their mats fixed. http://news.yahoo.com/s/ap/20101115/ap_on_bi_ge/us_runaway_camry There remains more to this story.

    • Joeaverage Joeaverage on Jan 06, 2011

      Okay Michael - let me see if I understand your point. I had a '49 Chevy truck with the gas tank inside the cab. Scary, scary, scary. Loved the truck but it was a death trap. I drove it daily - all stock - for a long time. When did Chevy quit putting the gas tank in the cab? The early 1970s? And this is the reason you avoid GM in favor of Ford? Wasn't the Ford denials about the Pinto in the 1970s too? Cheaper to pay the lawsuits than fix the car's design which needed cheap armor between the rear axle and gas tank I heard in the end. What of the Explorer/Firestone debacle? I'm just saying if we are going to pick ancient history to support our choice in brands then we are going to have a hard time finding a good fault-free brand. And this is all moot if I missed some news that says GM is back to putting the gas tank inside the cab.

  • Michael Plunkett Michael Plunkett on Jan 06, 2011

    Just like Chevy trucks were not an issue. I believe I even have an old copy laying around. But putting the fuel tank behind the seat proved deadly for dozens of people and eventually was changed. Not that you heard it here? Chevy trucks are great and no where else to put the tank I beleive was close to what you said. So many advertising dollars at stake the truth about cars from the manufacturers side only right? People probably died from this and toyota/lexus hid it with every thing they could find. Sure they have modified the software and maybe they fixed it and maybe not! They lied and covered up so why trust them now. Beside the quality has steadily decreased from my first toyota decades ago so I for one am playing it safe. I traded mine in on a Ford. And I will never venture into another Toyota (hired alot of ex GM managers) dealer.

  • Svenmeier Speedometer display in the center console screen? Why? This is a dealbreaker for me.
  • Alan I do believe that traffic infringements penalties based on income will affect those who are financial able to flout safety regulations.When I drive above the posted speed limit I assess my situation using probability. If I'm confronted with a situation where time is of more value to me than speed I will speed if I assess the probability of a fine to be quite low. I can afford the fine, what I can't afford is the loss of points on my drivers licence.In Australia (12 points in QLD and all States have a point system) we have a points system attached to your drivers licence. An open drivers licence is granted 12 points every 3 years. So, if you receive an infringement for exceeding the speed limit it takes 3 years for the points to be removed. I generally get caught once every 2 years.I think a points system would be a fairer system over a system based on income. Its about retaining your licence and safety, not financial gain by the government.As you can see below it wouldn't take long for many US drivers to lose their drivers licence.[h2]Current penalties for individuals caught speeding[/h2]InfringementPenalty amountDemerit pointsLess than 11km/h over the speed limit$287. 1 pointAt least 11km/h but not more than 20km/h over the speed limit$431. 3 pointsMore than 20km/h but not more than 30km/h over the speed limit$646. 4 pointsMore than 30km/h but not more than 40km/h over the speed limit$1,078. 6 pointsMore than 40km/h over the speed limit$1,653. 8 points and 6 month suspension
  • Wjtinfwb Instead of raising fines, why don't the authorities enforce the laws and write tickets, and have judges enforce the penalty or sentence of a crime. I live across the street from an Elementary School on a 4-lane divided state highway. every morning the cop sits in his car and when someone sails through the School Zone well above the 10 mph limit, he merely hits his siren to get their attention but that's it. I've never, in 5 years, seen them get out of the car and actually stop and driver and confront them about speeding. As a result, no one pays attention and when the School Zone light is not lit, traffic flies by at 50-60 mph in the 45 zone. Almost no enforcement occurs until the inevitable crash, last year some zoned out girl rolled her beater Elantra 3 times. On a dry, straight, 4 lane road with a 45 mph limit. I'm no Angel and have a heavy foot myself. I've received my share of speeding tickets, lots of them when younger. Traffic enforcement in most locales has become a joke these days, jacking prices because someone has a higher income in as asinine as our stupid tax policy and non-existent immigration enforcement.
  • Jeff S If AM went away I would listen to FM but since it is insignificant in the cost to the car and in an emergency broadcast it is good to have. I agree with some of the others its another way to collect money with a subscription. AM is most likely to go away in the future but I will use AM as long as its around.
  • BEPLA I think it's cool the way it is.If I had the money, time and space - I'd buy it, clean it up, and just do enough to get it running properly.Then take it to Cars and Coffee and park it next to all the newer Mustangs.