For example consider that both the Traction and Stability Control Units in the normal course of events go around casually applying brakes to one front wheel or the other as deemed appropriate, but if this somehow occurs unexpectedly with nothing suggesting that it is about to happen, it can lead to an uncontrollable turning motion, a force irresistible even if the driver knew it was coming, leading to swerving into another lane of traffic or completely off the road for example, especially dangerous if occurring out of the blue or during some other maneuver. The driver might not even recognize that such an event had occurred and police investigators would not even believe him even if he claimed it had occurred. Note that numerous Prius drivers have claimed this swerving motion happened to them and they all seem quite mystified by it, and seem not to have considered the basic feature of their electronic systems that would have made it possible. This may have happened to drivers of other brands of automobiles as well, but the Prius groups spend more time going into all sorts of mystifying things that have occurred to them, yet they seem to resist inputs from non-Prius drivers and people casting doubts about the Prius seem to have their rights to log on and comment quietly cancelled.

Many of the faults of which Prius owners complain online seem to be software related, but reading through lots of these posts reveal little if any attempt to define what the mechanism of the fault is. One would like to develop the simplest theory which explains all the known facts and to make predictions which could be tested by experimentation.

The Federal government requires that the newest jet transports monitor a minimum of 88 definite parameters in their “black boxes” but actually the manufactures have gone far beyond this, monitoring over 700 channels of data in the latest models, including lots of data from the engines, positions of controls in the cockpit, position of control surfaces, lots of data at intermediate points etc. In general these systems are designed to sort out intended from unintended (un-commanded) events (among other things.)

Data recorders are not mandated in automobiles for two more years but the Big 3 are generally installing them anyway and making readouts easily available to all interested parties whereas Toyota is holding on until the bitter end and will not have them until 2012. Flight data recorders in airplanes monitor over 700 channels of data typically several times per second, with much higher rates in burst mode if sudden changes are detected and typically record 17-25 hours of data. The requirements for automobiles are much less rigorous and not well described online. NHSTA has mostly been standing quietly by, waiting to see what the car manufacturers would do on their own. Good luck NHSTA, we are proud of you.

If Toyota really wanted to prove all its assertions about its electronics it would install data recorders capable of storing data for many hours from all significant sensors already on board as well as all commands issued to the hardware items. This would include all the signals (commands) to the brakes (pressure increase, decrease and hold) signals to the throttle and how these commands correlated with driver inputs from the gas pedal and the brake pedal etc. One should keep in mind that all commands to the throttle and brakes are merely “requests” since all systems are “fly-by-wire.” To repeat, there is no mechanical connection of the gas pedal or the brake pedal to the respective modules in the engine compartment.

Good data collection is increasingly feasible since digital memory is dirt cheap and getting cheaper, as well as coming in larger and larger capacities. Various “safety features” such as stability control will be mandatory in 2013, so it seems reasonable to establish ways to ensure that it is actually doing something for us. Perhaps supposed increased safety on the roads is due to over-zealous police action rather than any safety improvements in vehicles. This means that lots of problems caused by electronic “safety systems” can easily go undetected amid all the noise. Meaningful analysis requires breaking out the actual numbers, to place blame or credit where it belongs.

The ABS has yaw sensors to detect skidding sideways & speed sensors on all four wheels to prevent brake lockup, improving both stopping and steering . The ABS operates on slippery surfaces by using valves in the ABS brake control unit to increase and decrease braking forces at each wheel up to 20 times per second, yielding its familiar pulsation. The ECU simultaneously operates to reduce engine power as needed and this requires the ability to restore or INCREASE engine power when appropriate.

So next consider TRACTION CONTOL, which acts by detecting the drive wheel that is spinning the most and applying a braking force to that wheel, sending more power to the other wheel with less spin due to better traction and reducing engine power as part of the total effort. Note again that the system must be able to INCREASE (restore) as easily as it reduces engine power,

STABILITY CONTROL operates through the
Further, Toyota in its Prius model has this cute little feature that uses radar to help control the distance from the vehicle in front. Again one can see that the system must have the capability of either decreasing or INCREASING engine power and thus vehicle speed to get this done.

So we have all these neat safety features which depend on many different things operating perfectly in concert, controlled by computers, which must be operating without error. Notice that all of these features have the requirement of both decreasing and increasing engine power and vehicle speed. This provides the perfect mechanism to explain all the episodes of unintended acceleration UA that Toyota continues to deny, except to invoke bogus explanations like gas pedal entrapment under the floor mats and issues of stuck gas pedal which can be cured by inserting a magic little shim. These two explanations for UA meet with little acceptance outside of Toyota itself and those who seem to be their fan boys.

So my point is that all these software issues now interact with all the basic hardware features already on board to produce the PERFECT STORM for Toyota. So there was the well-publicized San Diego case of James Sipes, with the wild 20 minute 30 mile chase down the freeway, followed shortly by the case in Harrison NY where a Prius underwent UA from a standing stop and struck a stone wall. These two cases, the first at high speed and the second from a standing stop simply indicate to me that the PRIUS IS UNSAFE AT ANY SPEED.

(1) For example advice is given to simply press down on the parking brake. They only go to the rear wheels but they are completely mechanical, activated by cables. One only needs to sit in a Prius and play with the parking brake to detect the severe short-comings. It is clearly labeled to engage it with one press of the brake pedal and to disengage it with next push. So if one gives the parking brake a sharp clean shot with his foot, it goes down and stays down. But if he is nervous or stressed and wriggles it a little bit to make sure it is fully applied it comes unlatched and follows his foot up, something the driver might not notice. Or if it is applied and he checks and presses it again to make sure, perhaps because some police operator like in the James Sikes case in San Diego tells him to, well it come unglued. The lady talking to James Sipes was a “nervous Nelly” type anyway who seemed incredulous that the Sipes Prius was out of control in the first place. Not the type to inspire much confidence. The CHP along in his big Crown Vic had a much more commanding presence, demanding some respect at least.

(2) So next the driver is supposed to shift into neutral. So go sit in a new Prius in the showroom and check that one out. The Prius shift lever has a short throw and a vague feel, like a flight simulator game controller, that depends upon context for any meaning. But that is the whole idea, the Prius is sort of like a big video game much of the time, with all the video playing out across the dashboard, with many Prius owners especially the so-called hyper-milers trying to post big mileage numbers, so they can post them along their bio data on the Prius boards. The little tag on the steering column clearly states that the shift lever must be HELD IN NEUTRAL after shifting it there. I had not seen that one before. Besides shifting to neutral is “fly-by-wire” just like pressing on the brake pedal or gas pedal. The driver merely issues a request or a suggestion to the system. So nobody has really tested things out to see what would happen in the real-world, if somebody did actually shift a Prius into Neutral under WOT and failed brakes at high speed. Toyota won’t even admit that UA and failed brakes even occur and here they go telling us what to do about it
(3) Maybe Saylor the CHP cop did stand on the emergency brake and shift the little lever into neutral and neither did any good? How would we know? He and his family are dead and if there was anything on his EV Event Recorder, that indicated the true cause of the UA or loss of brakes or anything else incriminating to Toyota, Toyota could not be depended upon to help in its recovery and while pretending to attempt its recovery, would be in the perfect position to destroy all evidence and claim it never existed, actions which in the normal course of business would be called destruction of evidence and obstruction of justice. Again, Toyota should be forced to cough up everything having to do with those Black Boxes.
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(4)So the Government is not trying to hurt Toyota. Right on. Toyota and NHSTA until quite recently were going around the country conducting what passed for joint investigations and giving joint news conference and putting out news releases that NHSTA had bought into their story that everything had been checked out and nothing was involved besides driver error. Until it got so bad especially after the Saylor case in California, that NHSTA told them to stop it, that they were tired of being made the patsy like when NHSTA had to go before Congress and expose their incompetence to the world. Toyota frankly had been going around acting like NHSTA had been bought and paid for and they could use NHSTA as they pleased.

It is disgusting to see dealers such as this fluffing off valid complaints in such cavalier fashion. Such dealers seem incapable of expressing shame or remorse.

All the new “safety features” in new cars, such as ABS, Traction Control, Stability Control and Cruise Control, acting through common hardware elements controlled by computers are potentially death traps waiting to grab somebody. And considering the complexity of these issues, with the faults not necessarily confined to Toyota, the only realistic way to study these issues is the installation of data collectors on vehicles in question that will allow real-time collection of data in large quantities over long periods of time from large numbers of sensors. The sensors are already on board as parts of all the Emissions Controls and Safety Features. In addition one needs to capture the command and feedback signals from all the actuators, that is, what they were commanded to do and why, and how they actually responded. The other manufacturers are already largely in compliance with such rules as best can be determined by public information but Toyota is holding out to the bitter end, not saying how much of this data is already being collected and they are not sharing anyway, making the pathetic excuse that there is only one “special computer” in this country capable of accessing and evaluating this data.

Toyota claims that their systems save only several seconds of data and that only in response to an event forceful enough to trigger the air bags. But then they prove themselves liars by showing 20 minutes of data from the wild 30 mile ride of James Sipes, allegedly showing very rapid pumping of the brakes and full throttle application. But only when it seemed convenient. They could just as easily have destroyed the data if it had proved inconvenient. Toyota is not doing much to advance its own cause. David Strickland has declared them untruthful. I would add the terms deceitful and deceptive. Toyota needs to be brought into line and not with data collection systems of their own design.

What i do miss in this discussion is the following:
The cruisecontrol can cause acceleration. It is intended to do so!
When you have a cruising speed of 90 mph and you hit reset the car will accelarate to 91 mph. Now if you keep the control to reset it will accelearte until you let go (and for a lil longer to finish all impulses as i have noticed)

So the only way Jimmy’s story ads up will be a stuck (or software defected) cruise control.

I wonder if they (toyota etc) have tested that option, or if they have focussed on de pedals because they think that is the only defect toyota created.
But even then i bet i can stop the Prius without any problems.

1) No car reaches its top speed with brakes applied. The fishiest parts of his story are (a) Why didn’t he just reach over with his right index finger and flick the car into neutral? (b) Why didn’t stepping on the brakes send the engine speed back to idle (see point 2)? and (c) Why did he go 30 miles before doing what he finally did — press the stop button and turn the engine off?

2) In the 2008 Prius, when you press hard on the brake pedal, the computer sets engine speed back to idle. So there can’t be a struggle between brake power and engine power in this car. The computer will not allow that.

3) The hybrid power pack is not capable of producing full power for 30 miles. The traction battery would be drained well before then.