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Uncontrolled acceleration

Posted by john_g (My Page) on
Fri, Sep 18, 09 at 10:54

When we see reports of unintended acceleration the #1 cause is the driver inadvertently stepping on the throttle instead of the brake and not realizing the error.

In a panic, the last thing they think of doing is pick their foot up, and attempt to hit the brake again. This quite often happens when a driver hits both the gas and the brake at the same time, the throttle will bottom out, well before the brake pedal is fully applied. In a genuine instance of a runaway, the logical thing to do is slip the transmission into neutral, (the heck with the engine, it can be replaced if it over revs) and then turn the key off and pull to the side of the road.

The vehicle in this report uses Toyota's smart key system, and push button start. It is suspected that a misplaced floor mat caused a throttle application and prevented a full brake application. From there, the driver didn't know how to turn the vehicle off, and the car went screaming down the highway at 120mph until the accident occurred. Keep in mind, the driver as a police officer has a lot more experience driving at high speeds than any of us would, and in a pressure situation would likely think clearer than most people, after all that is what he is trained to do. Unfortunately, that was not enough to overcome this situation and as techs when we saw the report, we all realized we would not have known how to shut this thing down either and accomplishing that task would have been more accidental. I may have hit the "start" button, but would not have known to hold it for three seconds. This would have caused the steering lock to apply, but the park mechanism would simply have ratcheted, until the vehicle slowed way down.

http://www.usatoday.com/money/autos/2009-09-15-toyota-floor-mats_N.htm

Here is a link that might be useful: A very scary tragedy


Follow-Up Postings:

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RE: Uncontrolled acceleration

i was at a art fair years ago. vendors setup on sidewalk next to parked cars. i walked by an elderly couple in a car and the driver hit the gas and pushed the car ahead of him forward and went flying over the curb. the front of his car hit a doorway and the front bumper got hooked. i would say the car bumper was about 1 foot from missing the doorway. he proceeded to smoke the tires for about 30 sec till some fellow reached in an shutoff the car. there were dozens of people on the sidewalk in front of the car. very close to a major accident.


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RE: Uncontrolled acceleration

This summer, a lady friend of ours was run over by a SUV - while she was in a store! She was standing in front of a copy machine at Kinkos, making copies, when a SUV crashed through the store front, hit our friend and the copy machine. An employee zipped over to the vehicle and shut off the engine. Our friend was under the SUV with a broken ankle and other broken foot bones. She had other bruises - got beat up a bit. Luckily, the ground clearance of the vehicle was large enough to limit further injury.

Our lady friend spent the remainder of the summer in a foot cast and she is still on crutches. There was pain, too.

The driver of the SUV claimed the vehicle took off unexpectedly and had no clue. The accident did happen within a few seconds and required a quick reflexive response, but that corrective action was missing as the lady was in a panic mode the whole time. The vehicle jumped a curb, traveled across the sidewalk and through the store front, and then several more feet before it found my friend and the copy machine.

These kinds of accidents got me thinking that driver's ed should include more than the basics of starting, steering, stop sigsn, signals, and normal stops. It should include training for abnormal situations.


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RE: Uncontrolled acceleration

i am not sure what was going thru the guys head when he figured out the vehicle was stopped and he still had his foot on the gas? maybe put the car in park and shutoff the motor? maybe he was dazed. i was pushing my 1yr old child in a stroller and wanted to get away from the car, not get closer to it.


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RE: Uncontrolled acceleration

**The driver of the SUV claimed the vehicle took off unexpectedly and had no clue. The accident did happen within a few seconds and required a quick reflexive response, but that corrective action was missing as the lady was in a panic mode the whole time. The vehicle jumped a curb, traveled across the sidewalk and through the store front, and then several more feet before it found my friend and the copy machine.**

Unfortunately this is a pretty common occurance. Usually with a new driver or an elderly one. The driver usually misses the brake and steps on the accelerater instead. When the vehicle takes off, the instinct is to step harder. I've lived in a town of 5000 for the last 15 years. This same thing has happened at least twice since in this small town since I've been here.


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RE: Uncontrolled acceleration

I was witness to an event in front of my house about 15 yrs ago. A dear, very elderly lady lived next door. She was the daughter of one of the town's pioneer founders, was well known, had been a school teacher, and people looked the other way at her sometimes haphazard driving. (She was loosing control of her legs.) She was hard of hearing, but did not wear her hearing aid when she drove nor used the seat belt - we've seen these before. Both these factors played a role in what happened next.

She had one of the last models of a rear wheel drive Buick. She starts her car. Meanwhile, I guests are getting into my car for trip to a museum. It was misting rain and everything was wet. The rear wheels of my neightbor's car was sitting in puddle filled with leaves. The wheels spun as she gave it gas to back out of her driveway - she couldn't hear what was going on. The car began creeping slowly backward so she gave it a bit more gas pedal, and then the tires moved out of the slick leaf puddle and grabbed pavement that had more traction. The car lurched backward surprising the driver and throwing her into the steering wheel AND her right foot to the floor. Recall, she is not hearing much of this. She did not have enough strenght in her arms to push her body back - a seat belt would have been handy right then. The car launched across the street heading for the house on the other side. The lady recovers enough to make an abrupt steering correction. The car slowed in the soft, muddy yard, but the rear wheels are still spinning. She cuts half of a doughnut in his yard, the spinning tires making a rut about 5 inches deep and now the car is coming back across the street toward my car and my guest - PANIC. I junp behind a large tree; I thought for sure either my car or house was going to be the target, but then another steering correction and the car turned to brush against a tree at my front property line - It took off an outside rear view mirror. Her car shot down my propetry line and found another tree, an old 100 year old one with a huge root bole. Her car bounced off these roots using its rocker panel as a skid. This impact turned the car and it took off back across the street this time nailing a light pole. The car stopped. The top of the pole swung wildly like in the movies, and after 5 seconds, the hood of the light fixture popped open and the big sodium vapor bulb crashed to the ground. MInd you, this all took place with the car in reverse gear.

My wife was yellng at me to go over and help her out. I hesitated, and said, "I'm not so sure. Her engine is still running and I have to cross in front of her car." But, I did make my way over fearful of what I might find. As I approached the driver's side, she timidly rolled down her window and as I was starting to inquire if she was injured, she looked up at me and said, "Do you suppose this means that I will loose my driver's license?"

The week before, she had been ticketed for running the stop sign at main street.


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RE: Uncontrolled acceleration

An update to this story.

Here is a link that might be useful: LA Times


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RE: Uncontrolled acceleration

Many years a go, I was involved in a runaway auto. It was my folk's new 1955 Ford V8, stick shift. I had pulled onto a highway for an easy acceleration. There was no traffoc except for a car about 1/2 mile to my rear. Just as I eased it into 3rd gear and let out the clutch, the engine began to stumble and acceleration was less than expected, but I felt the gas pedal go to the floor. I stuck my toe under the pedal to lift ir up but there was no resistance - it was disconnected. The car began to gather speed. Realizing that something bad had happened under the hood, I slowed the car with the brake, pulled onto the shoulder and shut off the ignition leaving it in gear all the while.

Opeing the hood revealed the problem. The linkage between the gas pedal and the carbureator had fallen apart and the part dangling from the carburetor was jammed and holding the throttle wide open. its a good thing that on this car, the carbureator mixture became overly rich at WOT and casued the engine to stumble instead of going to full power.

I reassemblied the linkage and said prayer of relief. I had narrowly missed disaster. Apparently what had happened was that the car had been serviced a few minutes prior to this incident, and the serviceman had disturbed the linkage, but not snapped it fully back together. I reported this failuer to my parents and warned them to be on the watch of this hapeneing again. It never happened again in 80,000 miles.

On this car, the gas pedal is linked to the carbureator by a set of small rods having spring loaded, snap-together ball joints. The pivots were arranged to keep the engine motion on its mounts from moving the throttle. Not all cars of this era managed to completely negate the effects of engine motion. One notable example was a car with torque tube drive. When slowing to a stop, but in yet in gear, the engine was shoved forward causing the throttle to open some. This was a major cause of "surging" in that model.


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