Wednesday, February 03, 2010

Stopping a Runaway Toyota

I present a guest post today on the emerging dangers of buggy automotive circuitry, contributed by an expert in both law and physics -- my father Martin Cowan...

Do you have a Toyota or other car manufactured by Toyota (e.g., Lexus or Prius)? If not, do you have a car manufactured by anyone else?

One of the terrible accidents reported in the NY Times a few days ago described a 911 call from a panic-stricken driver (an off-duty police officer). He was screaming into the phone that the car was accelerating, that he could not stop it, and that the brakes wouldn't work. The call ended with the sound of a crash. He and his three passengers were all killed instantly.

As the stories unfold in the press, the problem is not restricted to the accelerator pedal, but also includes the brakes. Toyota has known of both problems for many years, but has tried to minimize it. For example, it usually blamed sudden acceleration on floor mats getting stuck on the pedal. However, in several accidents, there were no mats in the car (or they were found in the trunk). It is still minimizing the problem, claiming that the replacement of the current gas pedal will do the trick, even though this fix has failed before, and there is no hard evidence that that is actually the problem.

Moreover, the reports of brake failure cannot be explained by faulty gas pedals. The driver on the 911 call reported that the brakes were not working, and there are multiple stories elsewhere to the same effect.

The US National Traffic Safety Administration thinks that electromagnetic fields may be fouling the electronic circuits. Toyota denies this possibility (see yesterday's NY Times). But if this is the case, no cosmetic fixes like replacing gas pedals is going to work. Moreover, the problem may extend to every car manufactured today with electronic circuitry that controls its operations.

When I first started driving, several centuries ago, the gas pedal was connected to the fuel pump by mechanical means. Today, the gas pedal depresses a sensor, which sends a signal to the computer board. This board processes this signal, along with all of the other data being fed to it from other sensors, and determines how much gasoline and air to feed to the engine. It then sends another electric signal to a fuel injector than controls how much of the gas/air mixture is fed to the engine.

There is a similar situation with brakes and steering. Until about the 1950’s, when power assisted brakes and power assisted steering became available, both braking and steering were purely mechanical procedures. The brake pedal was connected physically to the brakes, and the steering wheel mechanism was directly connected to the front axle. Today, both the brake pedal and the steering wheel operate motors which do most of the braking and steering. You might still be able to operate the brakes and steering when the engine is off, but it would take a great deal of strength to do that, too much to be useful during an emergency.

We all know the frustration when our personal computers crash or freeze up. It happens all the time. In almost every case, it is just an inconvenience. We re-boot and the worst possibility is the loss of some data or the corruption of a file. When the computer in an engine in an automobile going 60 miles per hour “crashes”, so does the vehicle, and the damage to the occupants goes beyond an inconvenience.

What is amazing is that we have been using these devices in our automobiles for so many years and they have not failed more often than they do.

The possibility that electromagnetic fields can cause the electronics to fail is downright scary, We live in a sea of magnetic fields. Radio and TV signals, cell phone calls, overhead power lines, even sun spots generate these fields. The list is endless. While most of the fields are pretty weak, the effect may be cumulative. Moreover, we have no idea how many times we pass through much stronger fields during the day as we go by facilities using high energy equipment. Imagine the consternation in Silicon Valley if it turns out that the IPhone being used by an occupant in the automobile (not just the driver) is responsible! (Maybe that's why the Woz reported today that his own Prius has an overactive accelerator.)

It seems to this writer that this problem is not going to be solved by replacing a gas pedal. Worse, if it is a problem with the electronic circuitry, many other automobile manufacturers may find that they have similar problems. At the least, new cars will have to have better shielding for the electronics, as well as better redundancy and fail-safe systems, including perhaps, manual cutoffs operable from the driver’s position.

In the meantime, what should you do if you are in a car that starts to accelerate and you cannot control it?

Whether or not you think that you have a car that might have this kind of problem, you should still have a plan of action in mind should the situation arise. All the drivers in the family should go over this. You may also want to verify with your mechanic whether these work. Not every model of automobile will respond the same and the efficacy of these suggestions might have to be varied to account for the differences in your particular car. Don't be surprised if the mechanic doesn't know all of this, or only repeats the Toyota press releases. (If he just assures you that Toyota has already solved the problem, consider getting another mechanic.)

If the engine is racing out of control and the brakes won't work there are two possible ways to bring the car under control.

1) The better and safer method is the following:


This should work in all models. However, verify with your mechanic, or try it yourself at a low speed on a clear road. It is conceivable that, on some models, the transmission level merely operates some electronic circuits, like the gas pedal, in which case you might not be able to shift gears, either. I just don’t know.

Assuming that you are able to get the transmission into neutral, the engine will still be racing at full throttle, but it won’t be sending any power to the wheels. Unless there is something terribly wrong with all of the electronics in the car, and not just the engine circuit boards, the brakes and steering will continue to work properly, and you will retain full control over the vehicle. You should be able to stop it within a hundred feet or so. Even if the power brakes fail (as happened in some of the accidents reported in the newspapers), the car will eventually slow down by itself. You can also try to use the brakes manually—difficult without power brakes but not impossible—and apply the hand brake.

2) Another method, but clearly inferior, is to try to turn off the engine. If you can, the car will stop accelerating (unless you are going down a steep hill). But this won’t slow the car down very quickly (unless you are going uphill). There is still the problem of trying to stop it before it hits something really hard. If the engine is off, the power assists to both the brakes and the steering will be disabled, making it difficult to use the brakes and the steering. Depending on the design of the engine circuitry, the brakes might not work at all. If this happens, you can try applying the parking brake, although this is usually a very weak brake and it would take much longer to bring the car to a halt using this method. Finally, if none of the brakes work, you would just have to let the car roll to a stop. If it is going over 60 miles an hour on a level grade when you cut the engine, it could take a mile or more to stop the car this way. (My 1991 Mazda, which gets up to 38 miles to the gallon, might go 10 miles before stopping; my SUV, which gets 8 miles to the gallon, would probably stop in about 10 feet.)

Without power steering, you may still be able to control the steering at higher speeds (over 20 miles an hour), although you probably will need a significant amount of brute force to do this. When the car speed drops below 20, it will become harder and harder to control the steering wheel, but not necessarily impossible. Just takes even more force. Again, your car mechanic will know how the steering on your car would work if the engine is off.

The bottom line on this technique is that it is better than nothing, but can give you a lot of difficulty maintaining braking and steering control.

You should verify all of these suggestions with a mechanic who understands how the engine, steering and brakes in your particular car are wired up.

Meanwhile, all class action plaintiffs’ attorneys, rev up your engines. Your “action” is just beginning.


  1. When I studied EE a couple of decades ago, I had to take a mandatory course in Dynamics and I remember the professor explaining how power steering is always designed with a fallback allowing for unassisted steering in case of failure. I remember walking away from that lecture proud to be an (aspiring) engineer. It is amazing that contemporary car engineers ditched such a sound engineering concept. Let’s just keep in mind that we all take our chances any time we buckle up, and I’d like to see data confirming these events are statistically significant, i.e. do they move the car accident statistics needle?

  2. Anonymous3:01 PM

    it might be wise to not turn the key all the way to off - that would deploy the steering lock.

    In most cars moving to neutral will disconnect the drivetrain from the wheels. It should be noted that this would likely cause the engine to redline - beats banging into something really hard though.

  3. Anonymous2:40 PM

    It has finally come back and bitten them where it hurts. After years of trying to hide all of the defects with ALL of there CARS and TRUCKS it has come to roost. They just try to redesign the problem without telling customers about the problem. THAT IS WHY I WILL NEVER BUY ANOTHER TOYOYA AGAIN EVER.... The japs and chinese just thumb there noses at the US Govt and tell them to go screw off.

  4. Years ago TOYOTA & GM built the corolla & GEO in a plant in CALIF. They were identical cars with the only difference being the nameplate. However, when the data came out for quality defects, the GEO had 100% more defects than the corolla in the jd powers survey. No one could understand the results. Now i wonder if toyota has
    a way of somehow fudging the results or maybe american car buyers a more critical when filling out the surveys?

  5. Consider vacuum assist brakes. Vacuum
    is generated by deceleration. So when
    acceleration occurs, there is no vacuum assist for the brakes. It's no wonder the drivers are swearing that they have no brakes when SUA occurs.


  6. "street cars" not race cars, still develope an extremely high amount of vacuum even when at WOT. Test this your self by removing the brake booster vacuum hose off of its port. Place your finger over the opening as someone drepresses, or you manually open the throttle plate. You will see. BTW this whole unintended acc. thing is BS. It started with erratic braking as hybrids switched from regenerative braking to hydraulic. Now all accidents are being blamed on this instead of the true fault, OPERATOR ERROR.

    T.J. Maurer
    ASE certified technician.
    PS. I own a GMC not a toyota, and still stand by Toyotas as being great cars.

  7. I am a happy owner of Toyota Camry, as of my past 5years of Camry experience is very good, so really i don't think Toyota had a problem with their technology or assembling part, but their should be problem in their supply chain may some new third party less or no experienced company may joined and manufactured some parts with poor quality which causing huge damage to Toyota, wish they will disclose the truth to the public and apologies for what went wrong,
    Even after all those things any body ask me what's you next vehicle choice ?
    my ans is: Toyota

  8. Toyota may be hardly got effected due to their bigger presence in the automotive market, if you see statics we can say that compare with no. of vehicles on road vs no. of issues then Toyota have better record than any other company.