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Spring 2012 Vol. 12 Number 1

Table of Contents


A Final Word on
Unintended Acceleration

Reports of sudden, unintended acceleration in Toyota vehicles in 2009 and 2010 captured the attention of the media and the public. While complaints of vehicles exhibiting such behavior have been made for decades, the recent Toyota reports were complicated by the prevalence of electronic throttle controls. Although experts consider these technologies to be simple and well-proven, several consumer advocacy groups expressed concerns about their reliability.

The National Highway Traffic Safety Administration, the government agency responsible for identifying and mandating solutions for automotive safety defects, concluded that the 2009-2010 instances of unintended acceleration were due to drivers pressing the gas pedal by mistake and two other mechanical issues: pedals sticking or becoming entrapped by floor mats. NHTSA ruled out errant electronic throttle control systems as a plausible cause.

©iStockphoto/ThinkstockDespite NHTSA’s conclusion, public concern continued even after Toyota instituted recalls intended to fix the pedal issues. Faced with persistent questions about its decision to close the investigation of the electronic throttle controls, NHTSA commissioned two further studies: one from NASA released in 2011, and one from the National Research Council released early this year. NASA’s report supported NHTSA’s conclusion that electronic throttle controls were not a plausible cause of unintended acceleration.

The Research Council’s report similarly found NHTSA’s decision to close its investigation justified on the basis of the agency’s initial defect investigations. However, the report stated, “It is troubling that the concerns associated with unintended acceleration evolved into questions about electronics safety that NHTSA could not answer convincingly.”

In addition to weighing in on the acceleration issue, the Research Council’s report presents a forward-looking plan for NHTSA to authoritatively handle future questions about the safety of vehicle electronics -- questions the report says are bound to occur with greater frequency as these electronics systems become more complex, interconnected, and capable. NHTSA will need to become more familiar with how manufacturers design safety and security into electronics systems, identify and investigate system faults that may leave no physical trace, and respond convincingly when system-safety matters arise.

To guide the agency’s fulfillment of these critical responsibilities, the report recommended NHTSA step back and take an in-depth strategic view of the safety challenges arising from the proliferation of automotive electronics, and to assess how the scope, direction, and resources of regulatory, research, and defects investigation programs will need to be aligned to meet these challenges.

NHTSA will also require additional specialized technical expertise. “It’s unrealistic to expect NHTSA to hire and maintain personnel who have all of the specialized technical and design knowledge relevant to this constantly evolving field,” said Louis Lanzerotti, Distinguished Research Professor at the New Jersey Institute of Technology and chair of the committee that wrote the report. “A standing advisory committee is one way NHTSA can interact with industry and with technical experts in electronics to keep abreast of these technologies and oversee their safety.”

Electronic systems are critical to nearly all vehicle functions, including fuel economy, emissions control, comfort, convenience, and safety. The number of systems is expected to grow and provide substantial benefits to the driving public. The systems will also bring new challenges that NHTSA must face with confidence and expertise to avoid the recurrence of something similar to the unintended acceleration controversy.   -- Lorin Hancock

The Safety Challenge and Promise of Automotive Electronics: Insights From Unintended Acceleration -- Special Report 308. Committee on Electronic Vehicle Controls and Unintended Acceleration; Board on Energy and Environmental Systems and Computer Science and Telecommunications Board, Division of Engineering and Physical Sciences; and Transportation Research Board (2012, approx. 157 pp.; ISBN 0-309-22304-1; available from the Transportation Research Board, tel. 202-334-3213).

The committee was chaired by Louis J. Lanzerotti, Distinguished Research Professor, Department of Physics, New Jersey Institute of Technology, Newark. The study was funded by the U.S. Department of Transportation’s National Highway Traffic Safety Administration.

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Copyright 2012 by the National Academy of Sciences