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Discussion Starter #1
2013 Volt 33,000 miles

So my Wife is pulling into a parking space turning left from the parking lot travel lane. Car is nearly parked when she removes foot from gas. The car self accelerates. Before she gets the car stopped both passenger side wheels have jumped the curb stop. Then car continued across a small grass area and the front passenger tire jumps a second curb stop. The driver side wheels go to the left of both curb stops (steering wheel still turned left).

Once car is stopped she drives the rear wheel over the remaining curb stop and safely parks the car. The conditions were wet. Tire tracks indicate the front driver wheel was spinning at a high rate but achieving little traction. She says she was hard on the brake but car continued movement before stopping after jumping second curb stop. The car indicated a traction alert.

Had the car towed to the dealer it was checked by 2 techs including lead Volt tech. No codes, unable to replicate problem. Checked for indication of gas pedal recall (looked good). Undercarriage checked for damage none found. They were the small curb stops angled on both sides.

Did Google search this does not seem to be a common occurrence.

Wife refuses to drive the car again she was shook up pretty good. She is positive she was not on the gas. Stayed on the brake till the car stopped.

Did the only logical thing a husband could possibly do and traded it in on a 2017 Volt.
 

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My 2013 Volt accelerated while at a traffic light behind another vehicle but luckily I kept a great distance and restep hard on the brake about an inch from their bumper. I was also in Sport mode. Upon further inspection when I pulled into the nearest lot and found that the acceleration peddle got stuck the floor mat somehow. In my case I swap out with an all rubber mat and has since not encounter the incident again. Congrats on the 2017.
 

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2013 Volt 33,000 miles

So my Wife is pulling into a parking space turning left from the parking lot travel lane. Car is nearly parked when she removes foot from gas. The car self accelerates. Before she gets the car stopped both passenger side wheels have jumped the curb stop. Then car continued across a small grass area and the front passenger tire jumps a second curb stop. The driver side wheels go to the left of both curb stops (steering wheel still turned left).

Once car is stopped she drives the rear wheel over the remaining curb stop and safely parks the car. The conditions were wet. Tire tracks indicate the front driver wheel was spinning at a high rate but achieving little traction. She says she was hard on the brake but car continued movement before stopping after jumping second curb stop. The car indicated a traction alert.

Had the car towed to the dealer it was checked by 2 techs including lead Volt tech. No codes, unable to replicate problem. Checked for indication of gas pedal recall (looked good). Undercarriage checked for damage none found. They were the small curb stops angled on both sides.

Did Google search this does not seem to be a common occurrence.

Wife refuses to drive the car again she was shook up pretty good. She is positive she was not on the gas. Stayed on the brake till the car stopped.

Did the only logical thing a husband could possibly do and traded it in on a 2017 Volt.
Why is it always the wife that is driving?
 

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Most (all?) of these cases are applying the accelerator pedal unintentionally. I have also had this happen because of rubber floor mats getting stuck in the pedal mechanism or from the throttle freezing in sub zero temp on an old 300zx.

Common today is people checking a phone or some other distraction while parking and they push the wrong pedal without realizing. It is easier to do than you might think. I might have done so once, but was quick to catch it and didn't hit anything. I never stomp on the brake outside of an emergency so if I hit the wrong pedal I am not going to accelerate much. Tesla has had many notable incidents of this, and the issue there is the car has so much power it will launch itself through a building.

The Volt has hydraulic brakes, so if she was truly pressing the brake the car would have stopped despite unintended acceleration.
 

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Discussion Starter #5
My 2013 Volt accelerated while at a traffic light behind another vehicle but luckily I kept a great distance and restep hard on the brake about an inch from their bumper. I was also in Sport mode. Upon further inspection when I pulled into the nearest lot and found that the acceleration peddle got stuck the floor mat somehow. In my case I swap out with an all rubber mat and has since not encounter the incident again. Congrats on the 2017.
Anything is possible. However the factory floor mat was securely snapped in place.
 

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Most (all?) of these cases are applying the accelerator pedal unintentionally. I have also had this happen because of rubber floor mats getting stuck in the pedal mechanism or from the throttle freezing in sub zero temp on an old 300zx.

Common today is people checking a phone or some other distraction while parking and they push the wrong pedal without realizing. It is easier to do than you might think. I might have done so once, but was quick to catch it and didn't hit anything. I never stomp on the brake outside of an emergency so if I hit the wrong pedal I am not going to accelerate much. Tesla has had many notable incidents of this, and the issue there is the car has so much power it will launch itself through a building.

The Volt has hydraulic brakes, so if she was truly pressing the brake the car would have stopped despite unintended acceleration.
Part of the FMVSS standard is that all passenger cars sold in the US must have brakes that can stop the car even at full throttle.

One of the things I've always liked about GM is how difficult it is to get the floor mat caught in such a way for it to press the throttle open. Not impossible but difficult. My wife's Toyota Solara (same era as their unintended acceleration issues) is not designed well in this regard. The throttle stalk comes up from the floor vs. down in most GM cars - easy to have a floor mat related acceleration.
 

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AFAIK there have been a million claims of unintended acceleration and zero confirmed cases of it. I was with my wife a few months ago and witnessed a similar event. Quite scary since it's so unexpected. Unintended acceleration just means the driver didn't mean to accelerate, not that the car did. Your wife hit the accelerator rather than the brake pedal, and pressing hard made the wheels spin. Not a big deal. Accidents happen. People aren't perfect. Happily in this case there was no harm done.

The one instance where the Volt might give the impression of unintended acceleration is if it hits a slippery surface -- could be ice or a metal plate in the road -- and regen kicks out. You feel as if the car is accelerating but it's not, it's just slowing less quickly because regen is gone. Pressing the brake harder is the Rx for this.
 

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Brakes vs throttle, the brakes will win every time. She hit the throttle when she thought she was on the brake. It can happen to anyone. I'm sure she was freaked out but I'm glad nobody was hurt.

There have been many studies on this sort of thing. Usually it's someone who is a bit older and they're driving a car they are not totally familiar with. Like a new car, a spouses, or a loaner of some sort.
 

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I had a 1986 Ford Thunderbird. It was a 4 cylinder turbo ( "turbo-coupe" ) with 5 speed manual tranny. Several times this happened to me, you mash the gas pedal hard all the way to the floor, lift to shift but it's stuck on the floor mat. A power shift then a kick and its dislodged but yikes very disconcerting.
 

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A few times I moved my hand on the steering wheel such that I brushed the "resume" switch for the cruise control and the car did exactly that. That's unintended acceleration and notice the next gen steering wheels did away with that style of switch.
Yes, brakes are far more powerful than the powerplant. Think about it, the brakes can stop a car in a little more than 100 ft from 60 mph, can the motors do the opposite?
 

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Not unless you've modified the car to be a total hot rod, the brakes should have stopped the car. It sounds like the classic case of mixing up the pedals, as most unintended acceleration cases are.
 

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Given the extent of the overshot, it is likely a case of mistaken pedal, or a misaligned floor mat that caused acceleration pedal to get stuck.

Another possible explanation is that the Volts regen brakes stop functioning when road conditions are not ideal for traction (bumpy, wet, etc). Suddenly losing regen braking feels like the car is lurching forward, even though it is still slowing down but at a reduced rate of deceleration, until the operator detects the situation and applies more pressure on the brake pedal. It is possible that in this confusion (and panic), the wrong pedal was pressed by mistake.
 

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AFAIK there have been a million claims of unintended acceleration and zero confirmed cases of it. I was with my wife a few months ago and witnessed a similar event. Quite scary since it's so unexpected. Unintended acceleration just means the driver didn't mean to accelerate, not that the car did. Your wife hit the accelerator rather than the brake pedal, and pressing hard made the wheels spin. Not a big deal. Accidents happen. People aren't perfect. Happily in this case there was no harm done.

The one instance where the Volt might give the impression of unintended acceleration is if it hits a slippery surface -- could be ice or a metal plate in the road -- and regen kicks out. You feel as if the car is accelerating but it's not, it's just slowing less quickly because regen is gone. Pressing the brake harder is the Rx for this.
Actually there have been confirmed cases of unintended acceleration (UA). Audi had an issue in the 80s when taking the car out of Park and actually had to issue a recall to become the first manufacture to put the brake interlock system in. As a result, the FMVSS was updated to require all automatic transmission cars have the brake switch interlock system for moving the gear stalk out of park.

NASA's engineers who did the research on the Toyota unintended acceleration did NOT rule out a failure in the throttle potentiometer. They stated that while the Camry they were looking at didn't have a problem they did note electrical "hairs" on the throttle potentiometer. Their report also stated that these "hairs" were electrically conductive and that there existed a very small, but non-zero chance that given the number of cars with this potentiometer on the road that one could have a "hair" generated short circuit. In the Toyota throttle design at the time this would have been a signal to the ECU for a wide open throttle condition. I believe Toyota has since modified their design to prevent this failure condition from signaling WOT.

Floor mats - don't even get me started on how poorly designed some floor mat/throttle combinations are. GM tends to not have this issue with the pedals "hanging" from the engine/cabin firewall. Toyota at the time of the Camry UA issue was using "standing" throttles with the throttle arm coming up from the floor. The difference is that in a GM a loose floor mat will slide up under the arms of the pedals (throttle, brake, and clutch) making it very difficult but not impossible to press them down. In the Toyota design at the time a floor mat could press down these pedals if it shifted up improperly. My suspicion is this is what happened in the vast majority of the Toyota UA scenarios. While Toyota blamed aftermarket floor mats, the OEM floor mat in my wife's Solara periodically comes loose, twisting counter-clockwise, and sliding up towards the throttle. Fortunately in the Solara the shape of the foot-well prevents it from getting under the throttle and pushing down on the throttle stalk. GM uses a "snap" system to secure the floor mat, Toyota uses a "hook" that doesn't prevent the floor mat from being shook loose and the normal action of the driver's right foot can cause the right side of the floor mat to push back and separate from the hook, allowing the floor mat to twist around the left hook. The twist is invariably counter-clockwise as the driver's seat rail provides a physical block to twisting clockwise.
 

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Discussion Starter #14 (Edited)
I guess everyone is strongly leaning towards operator error. I have to admit this was my initial thought also. I am not trying to convince any one of the actual cause. I just have a few clarifying points for your consideration.
This car is my wife's daily driver.
Parking at work in the same area as always.
Factory floor mat was clipped into place.
Wearing the same everyday work shoes.
Cell phone or other distraction not in use.
Acceleration happens when foot is initially removed from gas.
Car is stopped within 15 feet with single brake application. (probably some reaction delay)
Forgot to mention in initial post. The car was shut down prior to restarting and intentionally going over the final curb stop.
 

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Several times my '12 (backed into the garage) will give me a lurch in the immediately after starting and putting into gear. I wonder if maybe it's if I start and immediately shift into reverse. It's very annoying, but the brake always stops it and I've only seen it a handful of times.
 

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I guess everyone is strongly leaning towards operator error. I have to admit this was my initial thought also. I am not trying to convince any one of the actual cause. I just have a few clarifying points for your consideration.
This car is my wife's daily driver.
Parking at work in the same area as always.
Factory floor mat was clipped into place.
Wearing the same everyday work shoes.
Cell phone or other distraction not in use.
Acceleration happens when foot is initially removed from gas.
Car is stopped within 15 feet with single brake application. (probably some reaction delay)
Forgot to mention in initial post. The car was shut down prior to restarting and intentionally going over the final curb stop.
Just one more reason to get rid of the hydra-matic (original name for the Oldsmobile automatic transmission) creep emulation from the Volt.
 

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Several times my '12 (backed into the garage) will give me a lurch in the immediately after starting and putting into gear. I wonder if maybe it's if I start and immediately shift into reverse. It's very annoying, but the brake always stops it and I've only seen it a handful of times.
You are either not using parking brake or disengage it early. Basically when you power on the thing and throw in the gear quickly the boot up sequence is not completed and power steering, power brake systems and drive motor are not available. If you have incline in garage, then the car will roll until the boot sequence is completed and car is ready to supply power either to brakes or drive motor.

Have gotten that million times and if you press the brake enough the hydraulics stop it anyway.
 

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Other than mistaken application of the accelerator pedal, the #1 is the floor mat.
Brake pedal, push into neutral, kill power, prying pedal up with toes are all ways to defeat the most stubborn unintended acceleration events.
 

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A few times I moved my hand on the steering wheel such that I brushed the "resume" switch for the cruise control and the car did exactly that. That's unintended acceleration and notice the next gen steering wheels did away with that style of switch.
Yes, brakes are far more powerful than the powerplant. Think about it, the brakes can stop a car in a little more than 100 ft from 60 mph, can the motors do the opposite?
yes,cruise control switch can be unintended acceleration given
 

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yes,cruise control switch can be unintended acceleration given
This is why the cruise control is inoperative below 40 KPH.
 
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