Nobody asked me, but . . .

Yesterday in WheelsTV I gave you a rundown (Actually it was a walkdown.) on some of Continental’s innovative technologies.  But I saved one for special mention today: Continental’s Accelerator Force Feedback Pedal (AFFP).  It’s one of Conti’s Human-Machine Interface (HMI) technologies, and I was able to evaluate it on a BMW 3 Series.  Instead of having the driver watch an upshift light on the dash or listen for a tone, the AFFP vibrates or adds a counterforce as feedback to the driver to educate his right foot in driving more efficiently to save fuel and reduce emissions.  Pedal vibration and/or counterforce are fully tunable.  This technology can also be integrated into several other Conti safety technologies, as for example, providing feedback to the driver of his current distance to other vehicles.

But I envision another more significant use for the AFFP: Alerting the driver that he has made a pedal error and is pushing down on the throttle instead of the brake pedal.  How would this work?  Let’s start by agreeing that the amount of force applied to the brake pedal in a panic situation is considerably higher than the amount of force ever applied to the throttle, even at wide-open throttle.  If the AFFP sensed a force higher than some pre-set figure, it would identify this effort as a driver hitting the wrong pedal: the most typical cause of unintended acceleration.  And the throttle pedal would respond with counterforce and a reduction in throttle opening to alert the driver that he was “braking” with the wrong pedal.   Pedal vibration could also be added, as long as drivers didn’t confuse this vibration with the brake pedal pulsations that occur when ABS is actuated.

At a recent symposium on unintended acceleration organized by the Motor Press Guild ( and hosted by the Auto Club of Southern California, John Tomerlin, who has conducted some of the most salient research on unintended acceleration and pedal errors was one of the panelists.   During the 1980s, Tomerlin published the results of his research into the causes of unintended acceleration in the Audi 5000 in Road & Track, Human Factors and in an SAE paper.

During the symposium Tomerlin introduced the concept of “fixing” the accelerator pedal and followed up later with the following comments:

The cause of classic unintended acceleration is pedal error, wherein the driver depresses the accelerator in the mistaken belief that it is the brake.  The problem was alleviated somewhat by Audi’s introduction in the mid-1980s of the brake-ignition interlock which assured that the driver’s foot was on the brake at startup, and also by a backup canceling of the throttle servo motor when the brake pedal was touched.  Neither system addressed the primary element in unintended acceleration, which is the accelerator itself.

As passenger vehicles continue to advance technologically–and driver distraction is increased by cellular phones, GPS, et al–the incidents of pedal error will increase.  No amount of driver education can guarantee proper control response in an emergency, or when the driver is distracted to a sufficient degree.  Ergo, it may be time to address the problem via the accelerator itself.

There are several ways in which this can be done, including (a) a “throttle interrupt” activated by extreme pressure on the accelerator pedal, viz 80 ft-lb/sq-in, or more measured at the firewall; (b) a voice warning at wide-open throttle; (c) a “black box” record of accelerator movement in relation to time, date, and force of impact in case of collision.  (The latter of relevance where unjustified product-liability is involved.)

My test procedures, reported by the S.A.E. and in Human Factors , demonstrate that relative sizes and positionings of the brake and accelerator pedals do not reduce the incidence of pedal error.  The accelerator pedal itself must be made an active part of the solution.

It would seem that the answer to Tomerlin’s request for an active throttle pedal is already sitting on the Continental parts shelf.  I’d love to hear back from anyone who can tell me why this is not a good idea.  Should I start with Toyota?

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