2010 throttle override safety measures

Why not try it yourself? Put the brake on while you apply accelerator pressure on a quiet street. I believe it has been posted elsewhere here that it will not kill engine rpm's, but it's a simple test to do yourself to see how it feels. You can shift to N (hold the lever to the side for more than a second), try that, too. It has been posted that the accelerator signal is killed then. Also, make sure your spouse knows to press the stop button for 3+ seconds if ever there is an occasion where she needs to stop the engine and all power while moving in an emergency (last resort). It's in the manual. Personally, I have no concerns. Floor mat acceleration can occur in any car with jammed mats, and only since electronic throttles has there been any way to override throttle pressure other than brakes and the switch--probably a good family discussion topic. That has happened to me when I had in my now-gone (not a Toyota) extra mat for rainy weather years ago.

 

Kurt2010,

I don't know at this point if the issue doesn't exist in the 2010 Prius or not. I have not experienced any issues with my brakes. But to hopefully answer one part of your post:

Toyota is not saving anything by not including the 2010 Prius. The Model years and Vehicles affected far outweigh the sales volume totals for the 2010 Prius. It's across many models.

I am not "overly" concerned but do plan on bringing up that question to my Dealership or Toyota on my first service visit. I too, noted my pedal to be smaller so maybe that was addressed in the 2010. As for the braking/throttle question, I will be raising it for my own satisfaction at the dealership and/or Toyota for clarification.

It would seem they didn't accidently leave out our 2010 models, unless something different is in place, but again I don't have any confirmations as of this date. If I do find something out I will post to this board as well.

 

You can only "try it yourself" if you experience sudden acceleration. You are suggesting that the problem can be recreated merely by holding the accelerator pedal down. I have no personal knowledge of the cause of the problem, but maybe you do. But there are many reports of the problem happening when there are no mats in the car at all.

I believe everything in the Prius is drive-by-wire, which means there are no mechanical linkages between the brake pedal and the brakes, or the shifter and the transmission. Instead, the computer systems are used to apply the brakes in response to depressing the brake pedal, and shift into neutral in response to moving the shifter to N. Maybe I'm wrong but I think a glitch in the software/hardware could render those attempts useless.

I would hope that the car would still turn off in response to pressing and holding the Power button, but I don't know. I'm not sure that would be a great solution at 100 mph, but I guess it would be better than waiting for the car to run out of gas.

I just hope the Gen III has no such problems!!!

 

Jim,

You summarized my thoughts exactly. I am not the least bit concerned about this. The floor mats are secured properly. The driver is aware of methods to mitigate acceleration in an emergency.

There has been a much higher frequency of throttle cables sticking on mechanical gas pedals than with DBW pedal position sensor failures. I don't embrace technology with a blind eye. I'm not an engineer, but I made a conscious effort to understand the hows and whys enough to put me at ease.

 

Every car has an override for stuck throttles. It's putting the transmission in Neutral. Then stepping on the brake.

 

I'm not particularly concerned. This car has so much better crash avoidance and crash safety performance than any of my previous vehicles that even if there is a real Toyota defect in there, I'm still much safer now than before. The fatality risk from this alleged defect has been tiny compared to my total traffic risk.

I'm more likely to be killed by a falling tree than a runaway Toyota. Seriously. This region (half a state) usually has one or two falling tree fatalities per year, but has already suffered three this month, including one on my normal evening walk route.

History suggests that driver error and mat interference account for, at minimum, the majority of runaway incidents. Having experienced both causes in prior cars, I no longer fear either.

Mounting evidence also indicates that many drivers fail to attempt an action that is natural to me -- shifting to neutral. I have heard very few allegations that this action failed, and then only in non-hybrids. Until some of these claims are substantiated, I'm not worrying.

 

But if your fly-by-wire gear shift knob is controlled by the same crashed computer that is calling for full acceleration you might be up that famous creek. What if the same crashed computer also scans for the power button being pushed? It's certainly a complicated system and I have no idea if it works this way or not, but it's something to think about.

What is needed is a totally separate fail-safe system that doesn't utilize any of the components/sensors used by the fly-by-wire computers. Maybe something like a separate switch to sense brake pedal actuation in series with an ICE manifold vacuum switch. If both switches are actuated it means that the ICE is at full throttle while the brake pedal is being trounced. When this situation occurs the circuit could open a relay for the injector fuel pump, thusly killing the ICE. This is of course, an oversimplified example, but it illustrates that a separate failsafe system could be designed to bypass a runaway computer system. I bet someone has a patent on it already.

 

As far as I know there has never been an unintended "acceleration problem" with the Prius.

The much publicized accident in San Diego that killed 4 people was not a hybrid car and was not even a Toyota. It was, I believe , a Lexus ES-350. The accident was not caused by the computer in the car or for that matter any other integral part of the machine. There was a non standard floor mat installed over the normal floor mat by a Lexus dealer that may have been instrumental. The accident could have been easily prevented if the driver had thought to simply put the transmission in neutral.

The Prius brake pedal is very much connected to the piston in the master cylinder just as it is in other cars. If the booster pump fails you still have brakes, you just need to press a bit harder.

No type of override or emergency shutdown is needed. In the very unlikely event you need to shut the car down while driving you can do it by pushing the power button for 3 seconds as mentioned above. But a far better and quicker way is to just put it in neutral which takes only 1 second and you will still have power brakes and steering. The engine will not over rev, it goes to idle speed when you put the shifter in neutral. A lot of us on this site have tried this and it works fine with no dramatics whatever.

As far as having some horrible computer failure that causes the throttle to stick wide open at the same time it renders the shift selector unuseable, I really think the odds of that are so slim that it just isn't going to happen. The odds of a similar failure in a totally mechanical system are probably much higher, or the chances of being hit by a meteor for that matter.

In other words there is no problem. The Prius is really a rather safe car, it's just a bit different and that scares some people.

 

You missed the original ABC News and Nightline stories that included a wrecked Prius in a creek outside Denver (slides #3-6).

I am unaware that a final investigation report has yet been issued in this case, or that the emphasized statements have been so concluded in any official report. Can you provide a story link?

A NHTSA crash site inspection report does indicate the presence of floor mat interference, and brake damage, but does not give a true cause, nor indicate whether or not the driver attempted to shift to neutral. Those remain as open questions.

 

Actually I am aware of this report but until there is good objective evidence indicating that there was a stuck throttle (stuck by something other than a floor mat) I don't put much faith in it, at least not yet.

I do remember the uncontrolled acceleration of the Audis which were driven through peoples garages etc. Turned out to be the foot on the wrong pedal as far as anyone can discover. Unless something is stuck under the brake pedal as well the brakes will stop the car even if you have full throttle applied, this is even true of cars that have several times as much power as a Prius or those old Audis. But you need to push the brake pedal down hard, if you put it down part way the brakes will overheat and quit working.

NBC News put model rocket motors in Chevy pickup truck gas tanks to get pictures of them burning after a staged accident. This was done to bolster a totally bogus report about GM building exploding gas tanks. Granted it was not ABC but I think they have the same basic mentality. Stories about evil cooperations sell.

I'm no big fan of GM (or Toyota for that matter) but I think we need to wait until all of the facts come in. Anytime there is a bad accident that is well publicized there will be a lot of people claiming it happened to them also, or to their relatives. Some of the time these are just people who are trying to get in on the big lawsuits.

 

Hi Tom,

No argument, it's a safe vehicle, and I'm not scared. I purchased it with full knowledge of the runaway Lexus. I've even been at the intersection where the accident happened.

But, there is still a risk with fly-by-wire systems that don't have failsafe overrides. Airbus had some crashes caused by over-reliance on computers, if memory serves. Another example of failsafe design is in railroad signaling technology. Any failure in the track sensors or control logic of grade crossing gates, for example, will result in the gates dropping. Better to fail restrictive and cause annoyance than risk someone getting nailed by a train they didn't see coming.

Once again, I'm not faulting Toyota, I'm just making general observations. Indeed, I just tried pressing on the brake while I was mashing the accelerator on my 2010 V. As the brake pedal is slowly depressed, it reaches a point where the ICE goes to idle. So this proves that at least in a 2010 Prius, a mat-jammed accelerator pedal will not cause a runaway event. My concern is what will happen if the computer fails, either due to a hardware issue, or a programming bug. That's when I'd like to see an independent system to initiate an orderly shutdown.

 

You have a good point, we don't really know what the software will do under all conditions and we never will, probably for any car. I think sometimes you just have to take your best shot and choose a car the seems OK. Believe me if Toyota turns out to be at fault I will be among the first to condemn them and apologize for not seeing it sooner. But so far all I have seen are some sensationalized media reports and no real objective evidence.

I think our families are as safe in these cars as they would be in any vehicle this size, at least I sure hope so.

I have seen video footage of the Airbus crash at the Paris air show some years back when the computer took control and decided to land the aircraft, kind of frightening. Fortunately we don't have a system that drives the car, the brakes are not fly by wire and they will override the engine if applied correctly.

I think your test, braking with the throttle down is a good one. Another good test if you haven't already tried it: consider finding an empty stretch of road and get up to 40 or 45 MPH, push the throttle clear to the floor and hold the shifter in N for a second. The car will go into neutral, the engine will rev right down to idle and when you see that it works you can just put it back in D and go on your way.

 

Just heard on the news that a Ford Fiesta had a runaway problem. The item stated that his cruise control got stuck on 100km/h and he could not stop the car. He could not disconnect the cruise setting or would the foot brake stop the vehicle.
Apparently he rang the emergency services and the lady who took the call told him to apply the hand brake as well as the foot brake.
This procedure worked and he came to a stop on the freeway.
He did say that since his situation received publicity he had had 6 emails from other drivers who had experience similar problems.
It looks like all cars should be fitted with a kill switch.

 

I am missing anything here where he made an attempt to put the car in neutral ??

 

I don't think you missed anything, the entire event may be a fabrication. You can be sure there will be a lot of people trying to jump on the "it happened to me too" bandwagon. This person may have been trying to get some publicity, get in on a lawsuit, or both. I think the people at emergency services (and 911 in this country) need to tell people to put it in N as well as applying the brakes when there is a stuck throttle.

We need some references if anyone knows of any. I did a couple of Google searches and didn't come up with anything.

Orf, why do you think you need a Kill switch? Haven't you tried holding the throttle to the floor and putting the car in N for 1 second? Here is an Edmunds video on You Tube that demonstrates, your Prius would not rev to the RPM limiter as the Mazda did in their test, it will just go to idle speed. No drama at all, but unlike the Mazda you have to hold it in N for 1 second. There is a video on this site somewhere that shows the same test with a Prius but I can't find it right now.

 

Maybe a round button on the dash that you need to hold in for 3 seconds (to avoid accidental kills) which kills the engine? Or a key in a slot? Neutral is a good option, so is the cruise control kill switch tied into the brake pedal. The guy that supposedly had the problem knows how the phone works, but not the car? I guess that's the condition we are in now.:Cry:

 

I agree with Tom with people jumping on the "it happened to me bandwagon". How easy is it to say that you experienced "unexpected acceleration", now that the media has sensationalized (sp?) this, rather than admitting you screwed up? Better chance for someone to pay for your mistake?

We had a woman jump the curb and run in to the side of the bank building where my son works last week. It was not a Toyota nor a hybrid, but at least this woman admitted that her foot slipped off the brake!

 

Are you talking about the 1988 Air France crash at that airshow?

Although there is a lot of mystery surrounding that crash, I'm unsure how you determined the three independent Flight Augmentation Computers "decided" to land the aircraft

First of all, modern high bypass turbofan engines, like the CFM-56 introduced in the mid 1980's, had operating quirks - they still do - that pilots were unaware of

The most important operating quirk is that it can take a long time, upwards of 15 seconds, to get to full thrust in a "panic" situation, eg application of TOGA (Take Off and Go Around) thrust. This may also be referred to as "spooling up"

Turbojets and low-bypass turbofans respond much more quickly. Turboprops can respond much more quickly yet again. However, consider that most prop stunt planes still use reciprocating motors, for instant throttle response

Second of all, the FAC's take in a variety of data to present on the screens, eg HSI. Not only barometric data, but also the radar altimeter. At low level, eg approach or departure, the radar altimeter is far more useful than barometric altitude data.

Third, the thrust-to-weight data of something like a civilian airliner simply does not allow for stunt flying. Something like a High Alpha pass should NEVER be done in a civilian airliner. Have any airliners, from either Boeing or Airbus, been allowed to perform High Alpha passes at airshows since?

Fourth, when properly configured for landing (Gear down, Flap/CONF 3 or Flap Full), the fly-by-wire Airbus will simply NOT allow reduction of thrust below safe minimums. This is known as Alpha Floor Protection. The aircraft will only allow modest reductions in thrust, otherwise the GPWS wailer will start screaming at you

So, regarding point 1: there have been windshear crashes as a result of the sluggish nature of modern high-bypass ratio turbofan engines, at low altitude, when a sudden TOGA thrust is demanded but simply not available. Low and Slow is very dangerous in a modern airliner

Point #2: was the Pilot in Command monitoring the barometric altitude or the radar altimeter? There appears to be a lot of confusion over that simple question, a lot of mystery too

Point #3: something like a fighter jet has an enormous amount of reserve thrust, as evidenced by the Power to Weight ratio. At an airshow event, something like an F/18 can literally do a Tail Stand in a High Alpha pass. Most civilian airliners will either deep stall and drop tail first, or simply refuse to let you perform the maneuver (Apply stick shaker/stick pusher, automatically apply TOGA thrust)

Point #4: I find this little point the most crucial. Simply put, the fly-by-wire Airbus would NOT have allowed the pilot to perform the High Alpha pass at the airshow

Under Normal Law, that is

Normal Law assumes all the FAC's are in the loop. Normal Law provides the following:

Alpha Floor protection
Overspeed Protection
Bank Angle protection
Pitch/Attitude protection
Load protection
etc

In Normal Law, the tricky part is Flare Mode, which is usually programmed for 50 feet. For most airliners, this can be a critical altitude, hence the fact that almost every modern Airbus and Boeing has the audible radar altimeter callouts eg "One Hundred," "Fifty," (Usually a chime at this point), "Thirty," "Ten" etc

In Normal Law, the squat switches in the landing gear must be tripped before reverse thrust can be engaged. Also, in Normal Law, if you are in Flaps 2, Flaps 3, or Flaps Full, and you intentionally reduce thrust to an unsafe level, eg an impending stall, the wailer goes off and you receive an audible "SPEED SPEED SPEED!" warning

You can also receive an audible "Don't Sink!" warning too

Contrary to popular myth, the Airbus allows you to "dump" various systems AT WILL. Eg: you can start dumping the FAC's to dump the protective envelope

If there are failures, or purposeful FAC dump, the next mode is Alternate Law. You lose the Alpha Floor protection, but retain basic low and high speed warnings

Another mode is Alternate Law/Abnormal, which dumps the speed protection.

The lowest level is full direct control, which is called Direct Law. Nothing protects you from stall, overspeed buffet, or tearing the wings off. I don't see how that pilot could have done the High Alpha pass unless he was in Direct Law

BTW, when that US Airways Airbus A320 ditched in the Hudson, the pilot did almost everything by the book. Once he lost the engines, the aircraft reverted to Direct Law, and he knew he had to ditch or risk either a stall, or a crash into tall buildings

 

An article about this event appeared in my local paper this morning.
It was not a Ford Fiesta but a 2002 Ford Explorer.
The article states that the driver was doing 80 km/h, not 100 as I thought I heard on the radio. A police car caught up with the vehicle, passed it, and waved other motorists to pull over to give room for the runaway. All told, he travelled 54 km before he was able to stop the car. Part of the episode was filmed from a chopper and later appeared on TV.
Apparently there had been a global recall for this model car due to a faulty switch that allowed drivers to disengage the cruise control by tapping on the brakes. Ford claim there is no connection between this runaway and the previous recalls.
I doubt that anyone would attempt to pull a stunt like this for publicity or to sue someone. The chances of getting into a position where one would either have to have an accident or disengage the cruise control to prevent an accident would be too great and the stunt would be revealed for what it was.
A kill switch would have to be something that would be easy to use in a panic situation, because many motorists would panic.
My recommendation would be to use the red triagle warning light switch that normally turns on both flashing turn indicators. Perhaps pushing that switch more than once within 2 seconds would do the trick.