Spaghetti Code in Toyota’s Software
The Toyota software case highlights the roles of risk, uncertainty, and the ethical responsibilities involved in designing safety-critical software. In 2009, a Lexus ES 350 suddenly accelerated to more than 100 miles per hour in San Diego and crashed, killing all four people inside. Toyota initially attributed unintended acceleration reports to floor mats and sticky gas pedals, but many victims and experts suspected that the electronic throttle system could also be involved. NASA engineers later reported that they found no evidence that electronics caused large unintended accelerations, but expert witnesses in a later lawsuit argued that Toyota’s engine control software was overly complex, poorly structured, difficult to test, and not designed to fail safely. The main question of this case is whether engineers and regulators should apply the precautionary principle when a complex software system may be causing serious harm, even before the exact bug has been proven. This case highlights the ethical danger of relying on poorly understood software in systems where failure can injure or kill people.