Test drove the subject vehicle.

The information gathered during this comprehensive effort does not support the petitioner's allegations. Consequently, his petition that ``NHTSA reopen its investigation into the phenomenon known as ``sudden acceleration''' is denied.

This petition denial will (1) discuss sudden acceleration and the Study, generally; (2) provide a general description of electrical circuit and cruise control operation, (3) assess each of the petitioner's three allegations, and (4) evaluate the alleged sudden acceleration incident occurring in Mountain Home, Arkansas on June 7, 1995.
2.0 The Issue of Sudden Acceleration

2.1 ``Sudden Acceleration (SA)''

The term ``sudden acceleration (SA)'' has been used (and misused) to describe vehicle events involving any unintended speed increase. However, the term properly refers to an ``unintended, unexpected, highpower accelerations from a stationary position [emphasis added] or a very low initial speed accompanied by an apparent loss of braking effectiveness.'' \9\ The definition includes ``braking effectiveness'' because operators experiencing a SAI typically allege they were pressing on the brake pedal and the vehicle would not stop. ``Sudden acceleration'' does not describe unintended events which begin after vehicles have reached intended roadway speeds.
\9\ John Pollard and E. Donald Sussman, An Examination of Sudden Acceleration (Cambridge, MA.: NHTSA, 1989, DOTHS807367), v. 2.2 The NHTSA Study

On March 7, 1989, NHTSA released a Report, authored by John Pollard and E. Donald Sussman, titled ``An Examination of Sudden Acceleration,'' documenting the agency's efforts (the ``Study'') to determine what was causing a relatively large number of crashes in certain model vehicles due to apparent unintended (and substantial) engine power increase and simultaneous loss of braking
effectiveness. Typically, these events began while the vehicle was stationary, shortly after the driver had first entered it. They frequently ended in a crash. While the phenomenon affected all automatic transmissionequipped cars sold in the U.S., some had notably higher occurrence rates, with the Audi 5000 eclipsing them all.\10\ The issue of ``runaway''Audi 5000's had been the
[[Page 25028]]
subject of NHTSA defect investigations and safety recalls, class action lawsuits, considerable media coverage,\11\ and public controversy. Internationally, the phenomenon was investigated by other governments during roughly the same time period.\12\
\10\ The sudden acceleration report rate for 1978 through 1987 Audi 5000's was 586/100,000.
\11\ Both print and electronic media reported on the phenomenon. Perhaps the most notable media event occurred on November 23, 1986 when CBS News' ``60 Minutes'' broadcast a segment entitled ``Out of Control,'' focusing on SA and the Audi 5000. The piece included a demonstration of an Audi 5000, extensively modified by a plaintiff's consultant. In an effort to demonstrate how, theoretically, Audi's were suddenly, and inadvertently, accelerating, he had drilled a hole in the vehicle's transmission and then, with the flip of a switch injected compressed air into it. Thus pressurized, the transmission linkage would open the throttle. In the 60 Minutes segment, produced by Allan Maraynes, the switch is positioned out of camera range and the accelerator is shown going to the floor on its own. Other than the modified Audi 5000 (which had been demonstrated to ODI engineers months before the broadcast), NHTSA has never found any production vehicle, of any type, with this sort of
configuration.
\12\ Transport Canada issued a report entitled ``Investigation of Sudden Acceleration Incidents'' in December 1988, concluding driver error caused the phenomenon. The Japanese Ministry of Transport released their report, ``An Investigation on Sudden Starting and/or Acceleration of Vehicles with Automatic
Transmissions,'' in April 1989, which concluded that there was no common mechanical cause for sudden acceleration.

To help resolve the issue and thoroughly explore topics not fully investigated previously, NHTSA Administrator Diane Steed ordered an independent review of SA in October, 1987 (the
``Study''). The Transportation Systems Center (TSC) of Cambridge, Massachusetts was commissioned by NHTSA to study SA and identify the factors which cause and/or contribute to its occurrence. Ten different make/model/year vehiclesall with cruise controlwere selected for particular scrutiny. Included among these was a 1984 Mercury Grand Marquis. Not all of the vehicles had unusually high SAI rates; some were chosen based on their use of certain design approaches seen throughout the industry. In this way, the Study's sample was reasonably representative of the United States' automatic transmissionequipped vehicle population as a whole.

TSC collected literature, individual case documentation, and data for each of the selected vehicles. Many drivers involved in an alleged sudden acceleration incident were interviewed. TSC studied and tested the vehicles' fuel, cruise control, and braking systems.\13\ The vehicles' driving controls were evaluated for both location within the cabin and operation. After gathering the information, TSC convened a panel (the ``Panel'') of independent experts in various disciplines \14\ to review the data and make recommendations. The findings and conclusions were to be published in a final report (i.e., Pollard and SussmanEd.).
\13\ In some instances, the testing was performed by NHTSA's Vehicle Research and Test Center (VRTC).
\14\ The curriculum vitae of all the panelists is included in Appendix A to the Report. The panel was highly credentialed, including Dr. John B. Haywood, professor of Mechanical Engineering at M.I.T. and Director of its Sloan Automotive Laboratory, and Dr. Phillip B. Sampson, Hunt Professor of Psychology, Tufts University.

NHTSA specifically directed that TSC and the Panel consider all potentially viable SAI causal hypotheses. Contributing factors were to be considered, as well. They were to develop tests for each of these hypotheses, through both engineering analyses and
experimentation, wherever feasible. In developing various
hypotheses, the following logical assumptions were used:

While applying these guiding principles, the Study covered:

At the conclusion of TSC's effort, comprising thousands of personhours gathering data; comprehensively testing vehicles including their systems and equipment; interviewing owners and drivers; and inspecting crash scenes and the vehicles involved; a report was released with the following conclusion: ``For a sudden acceleration incident in which there is no evidence of throttle sticking or cruise control malfunction, the inescapable conclusion is that these definitely involve the driver inadvertently pressing the accelerator instead of, or in addition to, the brake pedal.'' \15\
\15\ Pollard and Sussman, 49.
3.0 Electrical Circuits & Cruise Control

3.1 Electrical ``Power''

An electrical circuit may be defined generally as a system or part of a system of conducting parts and their interconnectors through which an electrical current is intended to flow.\16\ Electrical devices located within a circuit can only operate when the circuit is closed (i.e., the loop is ``continuous'') allowing electrical current to flow from its source, through the device, and back to the source. Switches are used to control whether the circuit is open (the device is off) or closed (the device is on). Switches may be mechanical (e.g., a wall mounted light switch) or electronic. The later includes transistors which respond to signals from other electronic components. Typically, switches are located in the positive (nongrounded) side of the circuit. ``Groundswitched'' or ``low side switched'' circuits refer to those where voltage (+) is always available at the device and the switch is located on the ground side of the circuit.
\16\ McGrawHill, Encyclopedia of Electronics and Computers, 1988, 128.

Power exists only when circuits are closed (by a switch) thereby allowing electrical current to ``flow.'' Typically, if an electrical device is operating even though its circuit is open (the switch is off), a ``fault'' bypassing the switch exists. These ``faults'' are sometimes generically referred to as ``short circuits'' or ``shorts.''

Even if an electrical circuit is closed, electrical devices only operate when sufficient power is available. In electrical
engineering, ``power'' is defined as P = EI where P = Power in watts, E = Electromotive force (emf) in volts, and I = Current in amperes. All electrical devices require a specified amount of ``power'' to operate properly. In the absence of adequate power, electric motors, for example, may ``run'' but will not be able to achieve their design speed. Other devices, such as solenoids, will not perform their function if there is insufficient power available. 3.2 Automotive Electronics

Motor vehicle electrical circuit and component operation conforms with the general description provided in the previous section. Until the early 1970's, there was very little use of electronics in motor vehicles. Prior to that time, automobile ``electronics'' comprised mostly auto radios, turn signals, and a few ignition systems. Then, with the advent of governmentmandated fuel economy and emission regulationsas well as certain safety requirementsthe use of electronics became more widespread and [[Page 25029]]
most all were of ``solidstate'' design.\17\ Solidstate electrical devices use transistors to, among other functions, control current without resorting to heated filaments, vacuum gaps, or moving parts (e.g., relays). Most of the cruise control systems in use since the early 1980's use solidstate circuitry.
\17\ The consumer electronics industry likewise was transformed with the advent of transistors. Today, most every radio, computer, cellular telephone, television, etc. is of solidstate design. 3.3 Cruise Control Operation

Cruise controls are the only automotive devices, other than the driver's feet, which can substantially affect engine power. However, unlike ``flooring'' the accelerator, which rapidly opens the throttle fully (wideopen throttle, or ``WOT''), most cruise controls (including those in Ford vehicles) require a few seconds to open the throttle, and most systems (including Ford's) are mechanically limited to only open the throttle approximately 80% of WOT. While this is a relatively large throttle opening, which may produce substantial amounts of engine power, rarely is the power produced enough to leave tire skid marks on dry pavement while accelerating from a standing start.

The following will focus primarily on certain groundswitched, electrovacuum cruise controls because the petitioner's theory involves these types of systems.

A typical groundswitched, electrovacuum cruise control is designed to operate as follows:

When drivers reach a speed they want to maintain with the cruise control, they press the ``on'' and then the ``set'' button. Pressing and then releasing the ``on'' button simply prepares the cruise control system to receive a signal from the ``set'' button (like pressing a VCR's ``on'' button prior to pressing ``play''). When the set button (a ``switch'') is pressed, a cruise control electrical circuit is closed. In some vehicles (including some built by Ford, GM, and Volvo), the cruise control system is ``groundswitched'' and pressing the button completes the circuit to ground. Only if: (1) The system is turned on and there is sufficient power to activate it; (2) the vehicle is traveling above a predetermined minimum speed (usually 25 to 30 mph); and (3) the driver's foot is not pressing the brake pedal; will the cruise control then engage to maintain the desired speed by holding the throttle open an appropriate amount. The throttle's position is modulated by a vacuum servoa bellowslike device. Typically, there are two electro magnetic valves (known as ``solenoids'') which maintain a vacuum within the servo. Vacuum is provided to the servo by the ``vac'' solenoid. The ``vent'' solenoidas its name implies'depletes servo vacuum. As long as the three conditions described previously are met, and when operating as intended, the solenoids activate only when the ``set'' button is pressed, closing the circuit.\18\ When the solenoids' circuit is closed, electrical powersufficient to activate the solenoids'causes the ``vac'' solenoid to open and the ``vent'' solenoid to close thereby maintaining vacuum within the servo sufficient to hold the throttle open only enough to maintain vehicle ``set speed.'' Other than through an electrical fault affecting the solenoids, the only way vacuum is maintained within the servothus holding the throttle openis by pressing the
``set'' or ``resume'' buttons (again, assuming all three pre conditions are met).
\18\ This also applies to circumstances where the ``resume'' button is pressed if the cruise control had previously been ``set'' and then deactivated by pressing the brake.

To ``turn off'' the cruise control (i.e., release servo vacuum), the driver either presses the ``off'' button which erases the speed memory in the cruise control module (``amplifier'') and opens the vent solenoid, or steps on the brake pedal. Applying the brake does two things: first it sends an electrical signal from an electronic dump switch (EDS) through the amplifier to the vent and vac solenoids which open and close (respectively) depleting servo vacuum. This electrical signal is normally sent to the cruise control system whenever the brake pedal is initially depressed about \1/16\ inch. Second, there is also a mechanical vacuum dump valve (MVDV) that opens every time the pedal is pressed (usually at least \1/8\ inch but rarely more than \3/4\ inches). The MVDV is a mechanical device designed to completely deplete servo vacuum should an electrical fault occur in the solenoid system that would prevent the EDS from functioning properly. Both the EDS and MVDV are designed to activate well before the brake pedal has been depressed enough to effectively engage the brakes. According to the Report (page 89) ``In virtually all recent designs for factorydesigned cruise controls [including Ford's], where digital circuitry is now the norm, two or more component failures are required to cause an unintended throttle opening.'' Faults affecting cruise control operation, and consequent vehicle movement from a stationary position while the brakes are applied, must involve simultaneous electrical (the solenoids) and mechanical (the MVDV and brake system) failures.

4.0 The Petitioner's Allegations

The petitioner claims that (1) NHTSA has failed to consider cruise controlrelated failures that ``bypass'' the cruise control ``control logic'' thus inducing SA in stationary vehicles; (2) NHTSA has never considered SAIrelated data gathered by the Ford Motor Company (Ford) involving ``2,800 incidents of sudden acceleration during 19891992;'' and (3) ``NHTSA has not addressed the fact that there is no true failsafe mechanism to overcome sudden
acceleration.'' \19\
\19\ Letter from Sandy S. McMath to NHTSA, July 19, 1999, 6.

This analysis will address each of these allegations in the order they were listed by the petitioner.

4.1 The Petitioner's First Allegation

The petitioner claims NHTSA should institute a new investigation into the cause or causes of sudden acceleration because it ``neglected to consider the mechanisms that can cause sudden acceleration by bypassing the control logic of the cruise control system'' and thus ``induce sudden acceleration in a stationary vehicle.''

4.1.1 The Cruise Control ``Bypass'' Theory

Since NHTSA completed its Study, SAIs and subsequent litigation have continued. Consultants for various plaintiffs have speculated that the SAI's were initiated by simultaneous, undetectable, electrical and mechanical failures of the cruise control system. This theory is based on their observation that some vehicles (including those produced in whole, or in part, by Volvo, Ford, GM, and Mercedes) are equipped with groundswitched cruise control systems and, consequently, the vent and vac solenoid circuits receive voltage whenever the vehicle's ignition is turned on. In their opinion, the SAI occurs when there is an unintended engine power increase due to a series of ground faults in the solenoid circuitry. According to the theory's proponents, these ground faults cause an inappropriate activation of the servo solenoids, opening the throttle.

The petitioner, presently representing the parents of two brothers injured in an alleged SAI,\20\ has retained Samuel J. Sero, a plaintiff's consultant.\21\ Mr. Sero has testified for plaintiffs in previous SAI lawsuits.\22\ Mr. Sero, and others, have testified that vehicles are prone to SAI where, by design, voltage is present at the cruise control servo solenoid circuits whenever the ignition is turned on. They have theorized that the subject SAI may have occurred because the vehicle's cruise servo may have inadvertently activated due to randomly occurring faults. The petitioner outlines the theory as follows:
\20\ See Section 5.0 for more details about this incident. \21\ Mr. Sero worked for the Allegheny Power Company for twelve years as a planning engineer, a standards engineer, and a
transmission lines engineer, investigating and maintaining the flow of electricity through the company's system. He is a licensed electrical engineer with a bachelor of science degree in electrical engineering from Carnegie Institute of Technology (now Carnegie Mellon University) in Pittsburgh. Mr. Sero has no professional experience in the auto industry and no human factors training. The theory propounded by Mr. Sero, and others, has never been published nor is there any literature in the automotive engineering field supporting it.
\22\ See Manigault and Jarvis.
``Mr. Sero has determined that the source of uncontrolled accelerations in Ford vehicles is the fact that voltage is supplied to the servo the moment the ignition is turned on. Under this condition all that is necessary to induce wideopen throttle [WOT] is a completion of the circuit to the servo. This can be affected by several discrete [separate] events and conditions that are completely foreseeable: (a) The ground connection to the printed circuit board [cruise control electronic control mechanism, or amplifier] is opened or removed and either the vent wire or vacuum servo is grounded; or (b) both the vent [solenoid] wire and vacuum [solenoid wire] are grounded at the same time; or (c) a transient fault condition injects a signal across the output section of [[Page 25030]]
the electronic control unit inducing an effect similar to (a) or (b).'' \23\

\23\ McMath letter, 1.

Scenarios (a) and (b) involve multiple ``hard'' electrical faults while (c) relates to an injected signal generated by strong electromagnetic fields.

ODI notes that Mr. Sero's theory involves only one aspect of sudden acceleration, i.e., an unintended engine power increase. None of Mr. Sero's scenarios, on their own, would result in a SAI which, by definition, involve high power acceleration and an apparent loss of braking effectiveness.

Mr. Sero's theory, as it relates to SA, involves simultaneous, undetectable electrical and mechanical failures. He has taken exception to the use of the term ``theory'' to describe his hypothesis, claiming:

It's not a theory. It's a reality. It will happen. If they [the solenoid circuits] both complete a circuit to ground, you go to wide open throttle.'' \24\

\24\ Jarvis, May 18, 1999 Daubert Hearing Tr. 28.

There are two problems with Mr. Sero's claim: first, as we've described earlier, the servo is mechanically limited so that it will only open the throttle approximately 80% of ``wide open throttle;'' and, secondly, Mr. Sero's theory ignores two key elements of an alleged cruisecontrol related SAImechanical failures of both the MVDV and vehicle brake system. To conclude that his theory adequately explains a SAI, an assumption must be made that not only did a simultaneous electrical failure occur involving the servo solenoid ground circuits but mechanical failure of the MVDV and brake system occurred as well. Therefore, Mr. Sero's belief that inadvertent cruise control servo solenoid activation explains SAIs is, at best, theoretical, where ``theory'' is defined as ``a proposed explanation whose status is still conjectural, in contrast to wellestablished propositions that are regarded as reporting matters of actual fact.'' \25\
\25\ The Random House College Dictionary (New York: Random House, Inc.), 1362.

Mr. Sero goes on to claim these faults would be undetectable.\26\ As of May 18, 1999 Mr. Sero himself had not been able to verify that the types of failures underlying his theory were actually occurring. While testifying as a plaintiff's witness in litigation involving the alleged sudden acceleration of a 1991 Ford Aerostar, the following exchange took place:
\26\ For example, during ``Dateline NBC's'' February 10, 1999 broadcast, Mr. Sero claimed that cruise control electrical faults may occur ``if there is water in the wiring,'' and ``if water does play a role, proving it would almost be impossible.''

FOR FURTHER INFORMATION CONTACT Bob Young, Office of Defects Investigation (ODI), NHTSA, 400 Seventh Street, SW, Washington, DC 20590. Telephone: 2023664806.