Archive for October, 2013

An Update on Toyota and Unintended Acceleration

Saturday, October 26th, 2013 Michael Barr

In early 2011, I wrote a couple of blog posts (here and here) as well as a later article (here) describing my initial thoughts on skimming NASA’s official report on its analysis of Toyota’s electronic throttle control system. Half a year later, I was contacted and retained by attorneys for numerous parties involved in suing Toyota for personal injuries and economic losses stemming from incidents of unintended acceleration. As a result, I got to look at Toyota’s engine source code directly and judge for myself.

From January 2012, I’ve led a team of seven experienced engineers, including three others from Barr Group, in reviewing Toyota’s electronic throttle and some other source code as well as related documents, in a secure room near my home in Maryland. This work proceeded in two rounds, with a first round of expert reports and depositions issued in July 2012 that led to a billion-dollar economic loss settlement as well as an undisclosed settlement of the first personal injury case set for trial in U.S. Federal Court. The second round began with an over 750 page formal written expert report by me in April 2013 and culminated this week in an Oklahoma jury’s decision that the multiple defects in Toyota’s engine software directly caused a September 2007 single vehicle crash that injured the driver and killed her passenger.

It is significant that this was the first and only jury so far to hear any opinions about Toyota’s software defects. Earlier cases either predated our source code access, applied a non-software theory, or was settled by Toyota for an undisclosed sum.

In our analysis of Toyota’s source code, we built upon the prior analysis by NASA. First, we looked more closely at more lines of the source code for more vehicles for more man months. And we also did a lot of things that NASA didn’t have time to do, including reviewing Toyota’s operating system’s internals, reviewing the source code for Toyota’s “monitor CPU”, performing an independent worst-case stack depth analysis, running portions of the main CPU software including the RTOS in a processor simulator, and demonstrating–in 2005 and 2008 Toyota Camry vehicles–a link between loss of throttle control and the numerous defects we found in the software.

In a nutshell, the team led by Barr Group found what the NASA team sought but couldn’t find: “a systematic software malfunction in the Main CPU that opens the throttle without operator action and continues to properly control fuel injection and ignition” that is not reliably detected by any fail-safe. To be clear, NASA never concluded software wasn’t at least one of the causes of Toyota’s high complaint rate for unintended acceleration; they just said they weren’t able to find the specific software defect(s) that caused unintended acceleration. We did.

Now it’s your turn to judge for yourself. Though I don’t think you can find my expert report outside the Court system, here are links to the trial transcript of my expert testimony to the Oklahoma jury and a (redacted) copy of the slides I shared with the jury in Bookout, v. Toyota.

Note that the jury in Oklahoma found that Toyota owed each victim $1.5 million in compensatory damages and also found that Toyota acted with “reckless disregard”. The latter legal standard meant the jury was headed toward deliberations on additional punitive damages when Toyota called the plaintiffs to settle (for yet another undisclosed amount). It has been reported that an additional 400+ personal injury cases are still working their way through various courts.

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On December 13, 2013, Toyota settled the case that was set for the next trial, in West Virginia in January 2014, and announced an “intensive” settlement process to try to resolve approximately 300 of the remaining personal injury case, which are consolidated in U.S. and California courts.

Toyota continues to publicly deny there is a problem and seems to have no plans to address the unsafe design and inadequate fail safes in its drive-by-wire vehicles–the electronics and software design of which is similar in most of the Toyota and Lexus (and possibly Scion) vehicles manufactured over at least about the last ten model years. Meanwhile, incidents of unintended acceleration continue to be reported in these vehicles (see also the NHTSA complaint database) and these new incidents, when injuries are severe, continue to result in new personal injury lawsuits against Toyota.

In March 2014, the U.S. Department of Justice announced a $1.2 billion settlement in a criminal case against Toyota. As part of that settlement, Toyota admitted to past lying to NHTSA, Congress, and the public about unintended acceleration and also to putting its brand before public safety. Yet Toyota still has made no safety recalls for the defective engine software.

On April 1, 2014, I gave a keynote speech at the EE Live conference, which touched on the Toyota litigation in the context of lethal embedded software failures of the past and the coming era of self-driving vehicles. The slides from that presentation are available for download at

On September 18, 2014, Professor Phil Koopman, of Carnegie Mellon University, presented a talk about his public findings in these Toyota cases entitled “A Case Study of Toyota Unintended Acceleration and Software Safety“.

On October 30, 2014, Italian computer scientist Roberto Bagnara presented a talk entitled “On the Toyota UA Case
and the Redefinition of Product Liability for Embedded Software
” at the 12th Workshop on Automotive Software & Systems, in Milan.