SUDDEN UNINTENDED ACCELERATION (SUA)

my feet wouldn't fit

 

Yes, left foot braking is a thing in Rally racing,,, But, none of this applies to the Prius because the car shuts off Go input if there is Stop input. "Soft soil" ?, even with a FWD car that allowed it,,, I can't visualize how that helps.

Curious,, does your wife also 'Left Foot Brake' ?

I can see where with this car, and that practice, it could be a recipe for disaster.

Example:
You're slowing to a stop / parking spot with your left foot on the Stop pedal.
But,, your right foot has moved the very light pressure Go pedal some, but you don't know it because of the way this car works.
So then, you remove your left foot from the Stop pedal and ,,, yee haa !!!

I'm sure this, or any other confusion with Left Foot Braking, could never ever happen with your wife.....

(There was a Brand new Chevy Bolt where the car shifted itself into reverse in the garage and crashed into the wall while the wife was home alone.
Big To Do. GM read the Data Recorder. A week or so later she admitted she was fiddling in the car and did it herself..)

But still, I was taught, and believe, Left Foot Braking is just asking for a problem.
I'm a pilot and I would never consider Left Foot Braking in a car.

I tried it flinging my old '60 Mini around gravel roads back when I was young and dumb.
I could feel that it changes the pitch and yaw of a front wheel drive car while drifting, but if you don't have lots of practice to know when, and if it will help you, it just slows you down. But it was a ? 42 ? HP FWD car....

 

But beware that this brake-gas 'shutoff' may not be the same across Prius model years. If my memory serves (which at this age is not assured), braking on the older Prii sharply limited but did not eliminate the gas engine input. After the SUA fiasco and hysteria, that engine limit was further reduced, but OP's 2011 may pre-date that change.

The bigger changes were on traditional cars with much larger engines, such as the Lexus in the San Diego catastrophe. Those cars really did have enough engine power to overheat and severely compromise braking, especially when wide-open-throttle (WOT) caused loss of vacuum to power the brake assist. The NHTSA brake regulations did not address the WOT case, and assumed an idling engine.

 

What I visualize is that a Prius with a stock braking system would not continue to roll forward with normal foot pressure applied to a normal brake pedal even if there were a large brick on the accelerator.
You’re presenting us with the mental picture of a Prius with a somewhat “modified” braking system that went off its leash and wound up ground looping in a parking lot.

I’m glad that nobody was hurt, but I’m also not visualizing how this was the OEMs fault.
Even if their car is partially to blame real-world, if I’m sittting on a jury I’m going to demand a fairly extensive explanation as to why your modifications did not cause your car to break - pun almost unintended.

The phrase that pays is:
For Off Road Use Only.

Remember....
As unscrupulous as Toyota can be....THEY are still defending the goal.
This means that YOU have to make the touchdown.

So far?
Fumble.

Sorry.

 

As someone who has forced charged their traction battery before (and on other Prii), there is enough force generated by pressing on the brake pedal as you press the accelerator pedal to keep the car in one place.

 

someone reported their brake pedal going all the way to the floor yesterday, and no braking. waiting for dealer finding this week.

in that scenario, i could see the creep potentially taking you where you don't want to go, if you forget the emergency brake.

but in all likelihood, the dealer will find nothing wrong and no codes stored

 

This has been an infrequent but ongoing issue since Gen3 was released. I even experienced it in my 2010. Some signs are consistent that the power assist / stroke simulator layer momentarily failing, such as might happen if the brake controller experiences a firmware fault. The pedal then falls down to the underlying and unassisted mechanical-hydraulic system. But this isn't the only possibility.

One of the consistently undetermined issues is whether or not the driver then applied full manual braking pressure to the pedal. Full body weight, or at least 112 pounds (metric for 500 newtons). If so, and if the brakes work, then the NHTSA-required fail-safe works. If the brakes don't work, then it is prima facie evidence of violating NHTSA regulations.

But with the surprise loss of power boost, combined with the majority of today's drivers having no experience with old fashioned manual-only brakes, many drivers simply don't respond correctly and don't escalate to the required manual braking force. Some even let go of the brake completely, assuming it no longer works at all.

IF there is a firmware bug causing this transient brake failure, then it needs to be isolated and fixed. Even if the NHTSA-required fail-safe still works correctly. But drivers also need to learn how to respond to such incidents. There is still no critical mass of sufficiently detailed reports on the first, and seemingly no progress on the second either.

Agreed, that has been the pattern so far. If there is a defect hidden there, lack of codes is part of the reason it hasn't yet been isolated.

 

To the OP: It happens all the time and in various brands but not the way you described. How many of these stories do you hear where someone steps on the gas and runs into and through the convenience store, barber shop, bakery, etc.? It happens every week in Los Angeles. At the end of the day you'll just have to admit your wife was pushing on the gas pedal and not the brake.

 

No, he doesn't have to admit this at all.

Despite strong evidence that most cases are driver error, and that the old fashioned mechanical causes and product defects have been greatly reduced, we have no rational reason to believe that machine faults have been completely eliminated. And after the deepest dive report into firmware quality to date, it would be a near miracle if there are no bugs lurking in there.

And this is not specific to just Prius. It applies to the whole field.

 

I think the plan is to wait for the jury to say that, after investing hundreds of hours with lawyers.

 

I still think that modified brake pedal will be your undoing, whether it's a factor or not to the actual crash.

Even if it had nothing to do with it, a judge or jury will see that and dismiss the whole thing regardless of how many times you say "RALLY" in all caps. Jury or Judge will see that you "Modified the Brake Pedal" and ring the the gavel to dismiss.

 

While entering a driveway with foot on the brake and almost stopped, our 2012 Prius accelerated on its own and destroyed a garage door. Filled a claim with insurance and took our vehicle to the dealer to check on any faults.
Posting this to back up claim from OP.

 

Not sure what to say anymore, sorry?

 

Are you a left foot braker?

 

Or a brake pedal modder?

 

What I find interesting in all these apparent 'Sudden Unintended Acceleration' or 'my car set fire' and other such events is that people create an account, make a complaint, then often vanish. I am *not* saying Slotredfish is in this category, for the record.

What I am saying is that Subjective joined in 2012, years before the event happened, so that lends a lot of weight to the experience he had.

I myself had a SUA event years ago; accelerating onto a roundabout, and the car when full throttle. The brakes barely worked (due to the high torque once the car was moving), so it was a case of instinct and driving slightly sideways around the roundabout. Afterwards, I chucked the floor mat into the passenger footwell, and ordered some new plastic clips which had broken off!

What worries me, in particular, about the Event Data Recorder, is that it records the throttle position, brake position, etc, etc. So, if someone in a panic presses the gas pedal rather than the brake, the EDR will record that.

However, the EDR just receives data from the other computers in the car. This means that, in any SUA event that was not caused by driver error, the EDR will show what the other computers were 'asking' for. A fault in the throttle system would then result in the EDR showing 'full throttle', even if the fault causing that condition was in whatever microprocessor is finally responsible for sending the data onto (presumably the CAN bus) about the throttle position etc. In this situation, the EDR would work against you, and a SUA event caused by electronic failure could (with the EDR data from a court order) land you in big trouble, especially if someone got hurt.

All that said, I do like my Prius, and in fact bought one for my mother. I have had thoughts about installing a fuel-pump cut off switch on the dash (a bit extreme but it would get the job done, mostly), but haven't had the time. But it is important to recognise that all cars these days have increasingly complicated computer systems which can, and do fail (due to hardware error, software, error, even random cosmic rays from space). A case in point is the Nissan Leaf. While I am still driving this, there have been some proven failures where the brake controller computer crashes; because it relies heavily on regen braking, you end up with almost no braking power. The government is looking into it. I wonder what the Nissan EDR would record for such an event (likely it would show you were driving along, but then 'failed to press the brake pedal', and rear-ended the person in front of you...

 

I think that the way you assume the data that is being recorded is possibly faulty. But I have no idea how this system actually works.
Any good data recorder captures much more than just the end result. This allows analysis after the fact of problems in algorithms, memory errors, data transmission errors etc caused by cosmic rays and other sources of noise. Of course all these things are supposed to be caught and handled...but if you don't log all of it how do you know?

Mike (designed the telemetry system for a Space Shuttle computer 30+ years ago)