Safety has been a key aspect in the automotive industry even from its earliest stages, but the importance with which it is regarded has become far greater in recent times. Currently the biggest compound annual growth rate (CAGR) in automotive electronics revenue can be attributed to safety applications. Increasingly car manufacturers are making safety a key selling point with which to differentiate themselves from their competition. But with a growing amount of electronics content making up a car's bill of materials, there is now a necessity to switch from the long-established best practices approach to well-defined universal guidelines. As a result, industry protagonists have joined forces to develop a standard with far-reaching implications.
The word "safety" is subject to various different interpretations. However, when applied to modern automobile design it can generally be categorized using the following structure:
1. Passive safety: Assuming that an accident is effectively inevitable, the aim of passive safety mechanisms is to minimize the severity of that accident. The passive safety elements found within a vehicle include seatbelts, crumple zones, etc.
2. Active safety: The systems that are concerned with active safety (based on the knowledge of the current state of the vehicle) will aim to avoid accidents altogether in addition to the minimization of its effects if an accident occurs. Seatbelt pre-tensioning, airbag deployment, predictive emergency braking, anti-lock braking systems and traction control are all examples of this.
3. Functional safety: This focuses on ensuring that all of the electrical and electronic systems (such as power supplies, sensors, communication networks, actuators, etc), including (but not limited to) all active safety related systems, function correctly. Functional safety is dealt with by the ISO-26262 standard (published in November 2011).
It is important to state from the beginning that functional safety does not mean that there is no risk of a malfunction taking place -- instead, functional safety implies the absence of unacceptable risk due to hazards caused by malfunctioning behavior of electrical and electronic systems.
Figure 1: Translation from functional safety goals to hardware design, with associated validation & verification. For higher resolution click here.