With the wider use of electronic devices and systems in cars, the safety implications of electronic systems have become evident. According to reports from the USA, numerous fatal accidents have occurred due to sudden acceleration. Accidents in Sweden have also been reported. At the request of the Swedish Road Safety Office, the Swedish Defence Research Establishment has carried out a risk assessment of a cruise control system in order to establish its safety performance. This system, made by Hella, is an optional device in many common cars. It comprises electronic as well as mechanical and pneumatic subsystems. By means of reliability analysis methods such as fault tree analysis and fault modes and effects analysis, some single-point-fault modes are disclosed. The risk assessment, verified in tests, shows that a single fault such as a bad solder joint causes sudden acceleration. This means that the alleged events are possible. This disclosed single-point-fault mode establishes an upper limit for the safety of this cruise control. (A)
Abstract