We've heard the story dozens of times. "The car just took off!" they'll say. "It was possessed. The harder I pushed on the brake, the faster it went."
Back in the 1980s, the thoroughly non-specific term "unintended acceleration" came into wide use when Audi was under the gun for vehicles that reportedly took off on their own. In fact, it turned out that people were pressing on the gas pedal by mistake instead of the brake. Audi subsequently changed the placement of its pedals to forestall this unconscious confusion in the future.
Today public attention is focused on Toyota and Lexus. The reasons for the revival of concerns about unintended acceleration are different (interference from unsecured floor mats and sticking accelerator pedals, which are the issues addressed by Toyota), but some suggest that other explanations might lurk beneath the surface.
But we are not here to solve the question of why people experience unintended acceleration. Whatever the reason, the driver didn't have time to figure out the cause of the vehicle behavior in the heat of the moment.
All we care about is the acceleration itself. The question is, should such a thing occur, how do you save your skin?
Neutralize
In the past, we've recommend that drivers with what seems to be a stuck throttle do their best to shift the transmission into Neutral before they do anything else, pronto. Sure, the engine will race. It will bounce off its rev limiter. It will make a hellacious racket. But it will stop propelling the car forward. The noise is, in fact, a sign that this is so.
Once in neutral, the car is coasting and the driver can easily brake the car in a normal fashion and simply pull over. Once the car is stopped, there's plenty of time to shut down the engine and sort things out. It's simple, it works and it's still our top recommendation.
But some people don't think that way in a panic. Understandably, many see the brakes as the first line of defense when you want to slow down, whatever the reason.
Braking
There is a flaw in that thinking — a flaw that can be easily overlooked in the split-second it takes to decide how to react. The engine is still driving the car ever-forward and this makes the job of the brakes (and the panicky driver) that much more difficult.
As automotive testing professionals, we know in our bones that brakes have enough capacity to stop a car with a wide-open throttle. But we don't usually test that aspect of brake performance. So we don't have any data to pass along to you, the reader.
This calls for a test.
So we brought a 2010 Toyota Camry SE V6 and our VBOX data logger to the drag strip at Auto Club Speedway in Fontana, California, to make a few runs. The V6 makes some 268 horsepower, only 4 ponies less than the closely related Lexus ES 350, a car that has been involved in some highly publicized incidents.
Results
For a baseline, we made normal stops from 60 mph, just like we do week in and week out during our testing of hundreds of cars every year. Our test driver, Senior Road Test Editor Josh Jacquot, brought the Camry to a halt from 60 mph in 120 feet.
For his next pass through the test, at the same 60 mph, Josh floored the throttle to wide-open throttle (WOT) and held it there, then shifted into neutral just before mashing the brake pedal. The resulting stop of 121 feet is more or less the same as the braking performance that we recorded in this car under our usual test protocol. No surprise there.
Then we had Jacquot hold the throttle at WOT while leaving the transmission in Drive, which would be the worst-case scenario for unintended acceleration. It took more effort as the transmission downshifted and the determined engine fought to propel the car forward, but even in these extreme circumstances the car came to a stop from 60 mph in 149 feet. Longer than before? Sure. But we've tested SUVs in normal circumstances that didn't stop much shorter than this and no one has complained. Moreover, Jacquot made a second pass using WOT with the car in Drive and this time managed to stop in just 129 feet, simply because he knew what to expect.
But we weren't done just yet. As an encore we devised the worse possible scenario for an episode of unintended acceleration: a wide-open throttle with no power assist to the brakes. For this we disconnected the brake booster and drained the vacuum before sending Jacquot on his way. This time it took him 167 feet to stop from 60 mph on his first attempt. We repeated the test a second time and the distance required to stop the car dropped to 141 feet, again a side-effect of knowing what to expect. At the same time, with no power assist, the pedal effort required to stop the car was substantially higher than under normal circumstances.
But even this stopping distance compares favorably to a normal panic stop on wet asphalt.
What We Think
Can a car's brakes stop a vehicle with a wide-open throttle? Yes. In fact, we were able to generate surprisingly short stopping distances, even with the power assist utterly removed from the picture.
But we're not convinced that the average driver — a driver that has never strapped on a helmet or been to a test track — will push hard enough, fast enough on the brake pedal to get such a short braking distance under wide-open throttle (whatever its cause). If you apply anything less than the amount of force required to stop, you'll essentially be dragging your brakes and heating them to the point of failure, not unlike the folks who lose their brakes by riding them too much down a long mountain grade. At some point, there will be no brakes left.
That's why we still maintain that shifting the transmission into neutral before braking is the best way out of this mess (whatever its cause). An engine at wide-open throttle can't harm you if it's disconnected from the wheels.
The manufacturer provided Edmunds this vehicle for the purposes of evaluation.
Add A Comment »
wwest says:
05:59 PM, 03/06/2011
Listen to the engine NOISE, 36-38 second mark, as the car comes to a stop in neutral.
Now listen for the engine noise, 45-47 second mark, in the simulated UA test.
Not there, is it..?
diggertsi says:
07:11 PM, 03/27/2010
Just like the Audis in the 1980s, I think there is a perfect correlation between the "runaway" cars (any manufacturer) and their having automatic transmissions. A driver of a manual transmission car is far more involved in the actual operation of their vehicle, knowing that there is and having more than one way to *control* the amount of engine output that does or does not get to the transmission and wheels.
The comments about inattentive drivers, drivers without any real knowledge of, let alone interest in, how their vehicle actually works are bang-on. The vast majority just want their car to be an appliance that gets them from A to B with as little effort as possible on their behalf.
Any common sense expressed here is merely preaching to the converted.
kjgood says:
09:23 AM, 03/23/2010
It's a good thing that Inside Line has provided the basic, and painfully obvious, primary recommendation to shift the vehicle into neutral. What seems incredible to me is how few drivers seem to have a clue about the simple and very quick procedure to remove drive from the driven wheels (i.e., do some of these folks have no idea why there's a big "N" in the shift gate?), and for that matter how little this basic measure has been mentioned in the national media. While the root problem is apparently mostly Toyota's, protecting yourself by understanding basic functions of your vehicle, especially in emergency situations, is the responsibility of the driver.
Being an older guy, I have lived through years of driving when cars were far less reliable, and all manner of wonderful failures could happen. Total brake loss while going down a significant hill was one such example, and no, I didn't wreck the car. Perhaps that's the answer - modern cars tend to be so utterly reliable and easy to operate, that "emergency mode" due to mechanical issues are very rare, and drivers are not well prepared for them.
To bagachin's remark of "why not just switch off the engine?" I would suggest this: Yes, that too is a possibility, BUT drivers of most vehicles which have a conventional steering column lock switch would need to be very careful. Generally, one click shuts off the engine and leaves the steering wheel unlocked, but one more click locks up the column.... not very desirable when traveling at speed. I am skeptical that if a driver is not swift enough to find neutral with the gear lever, they are going to handle the switch-off at speed correctly. Inside Line is correct here - put it in neutral, get the car stopped and off the road, then switch off the engine. If the rev limiter doesn't keep the engine from blowing up while it's still racing in neutral, so what? Toyota will have to foot the bill for that too. Save yourself, and to heck with the engine.
bagachin says:
03:48 AM, 03/20/2010
Not sure if it was mentioend before. But why not just switch off the engine (e.g. pull out the key) and then hit the break when the auto acceleration occurs? Or it won't kill the engine by doing so?
sniperruff says:
08:52 PM, 03/17/2010
typo:
"But we weren't done just yet. As an encore we devised the worse possible scenario"
worst, not worse
lmbvette says:
08:38 AM, 03/17/2010
Back in college I had a 91 Corsica with a whopping 95 hp. The accelerator pedal would get stuck by the winter mats, or so I thought. When this happened, I'd freak out a bit because it would usually occur when pulling out from a stop and into traffic. So, there were usually lots of things to hit. I would just keep kicking or stomping on the pedal until it released. If it didn't, I'd pop it in neutral. Even though I did this, it was still scary because it would catch you off-guard.
It turns out the problem was not with the mat, but an improperly installed aftermarket cruise control. Back then, everything was mechanical. With the typical cruise controls there was the throttle cable and the cruise cable. So when the gas pedal was pushed it would cause the cruise control cable to slacken. The slack cable would loop around an exposed screw, thus pinning the throttle. Yeah, great installation job, eh?
juan_mx says:
07:49 AM, 03/17/2010
jason:
Yes, may be it is a wild theory, but I still believe that the ABS system may have some role in the cases the drivers claim they could not stop the car.
I think you can agree that the first reaction of any driver is to press the brake pedal as hard as necessary to stop the car.
The test by Edmunds proves that a car can be stopped by any driver, and that it is unlikely that if you press hard enough the brakes they will get hot enough to fade (there is no time to heat up beyond normal temperatures given the stopping distances they show in the test).
The ony explanation I can think of for the cases that claim that they were not able to stop the car (if they are real of course) is some malfunction of the ABS system.
Of course I am ruling out panic, other unforeseen rections by the driver (like pumping the brakes), or wanting to get money from Toyota.
About holding the car with the brakes in Drive at WOT, thank you for your answer, I have little experience driving automatic cars. All my cars have manual transmission.
johnferinal says:
12:20 AM, 03/17/2010
I would imagine that most people would freak out when things like this happen to them. However, the other day, I saw a guy who was talking about how to stop these cars with both feet on the accelerator and the brake. I never do that before in my driving years. I always get my foot off the accelerator and step on the brake when i do want to stop. Yeah, furthermore, changing to neutral would be the best solution. I think that there is a big movie about a car runaway, and a lady managed to stop the car somehow.
At the end, we cannot blame the customers for having these accidents. I have a toyota and am Toyota car fan, but Toyota needs to take responsibility to fix these problems to get back their image. This includes closing american plants and stopping dealin with american suppliers which make these crappy cars and parts.
jmaroun says:
10:51 PM, 03/16/2010
These videos were done by professional drivers, in a premeditated test. It is important to appreciate, that in a real incident of locked throttle, things will be far more stressful and alarming. In the real event, it is reasonable to allow some time for bewilderment and confussion before rational judgment kicks in. The amount of this time will varry from one person to the next. Sadly, that amount of time may make the difference between a life or death accident. Fact is, if this stuck accellerator problem is real, Toyota had better fix it fast, and own up to its responsibilities. In this case, I think the onus is on Toyota to convince its customers that their cars are safe. Until then, I won't be buying a Toyota, not even used.
cjsg35 says:
08:56 PM, 03/16/2010
so as fate would have it my GF's mom has a Camry and is apparently one of the ones who had this accelerator problem happen to her... i asked her what she did.... she said i turned the car off and coasted to a stop with my flashers on.... (BTW she was on the turnpike during rush hour) she is 77 years old... (im sure i'll hear about saying that but oh well) anyways if she can figure out how to safely control her car then i have no pitty for those who cant figure it out... I think its far time they stop reporting on this issue and let toyota handle it... and toyota needs to stop running those stupid apology comercials... its degrading to there company