Understand the term. See an example. Connect it to the bigger picture.
Part 1 · Part 3 · Part 12AIS
Abbreviated Injury Scale
An injury-severity classification scale used as supporting information when reasoning about harm.
For exampleA HARA rationale uses injury information to support its severity estimate.
A useful distinction
AIS and the HARA severity classes are different classifications; do not substitute one label for the other without justification.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 2 · Part 3 · Part 4 · Part 5 · Part 6 · Part 7 · Part 8 · Part 9
Acceptance criterion
A defined condition used to decide whether a work product or result is acceptable.
For exampleA test states its expected response and allowable timing before it runs.
A useful distinction
Acceptance criteria are not the same as a result recorded after the test; vague wording makes objective judgment difficult.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
This term also appears in 57 training topics. Search your assigned training to put it into practice.
Part 1 · Part 3 · Part 4ACC
Adaptive cruise control
A driver-assistance function that adjusts speed to help maintain a selected distance from traffic ahead.
For exampleThe vehicle reduces its commanded speed when it approaches a slower vehicle.
A useful distinction
ACC is an example vehicle function, not an ASIL classification or a claim of autonomous driving.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1 · Part 5 · Part 11ADC
Analogue-to-digital converter
A hardware function that converts an analogue input signal into a digital value.
For exampleAn ADC converts a sensor voltage into a number used by the controller.
A useful distinction
Conversion resolution does not by itself establish accuracy, diagnostic coverage or safety.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
This term also appears in 1 training topic. Search your assigned training to put it into practice.
Part 1 · Part 5 · Part 11ASIC
Application-specific integrated circuit
An integrated circuit designed for a particular application or set of functions.
For exampleA custom interface ASIC processes a sensor signal.
A useful distinction
Application-specific does not imply functional-safety qualification or a particular ASIL.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1 · Part 4 · Part 5 · Part 6
Architecture
The structure of an item or element: its building blocks, boundaries, interfaces and allocation of requirements.
For exampleA steering diagram shows sensors, controller and motor, with the requirements assigned to each.
A useful distinction
A block diagram alone may omit interfaces and requirement allocation needed to explain the architecture.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.1
Part 1 · Part 5 · Part 11ALU
Arithmetic logic unit
The processor hardware that performs arithmetic and logical operations.
For exampleAn ALU calculates a value used by a control algorithm.
A useful distinction
The ALU is part of a processing architecture, not the complete CPU or the whole safety mechanism.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1 · Part 5 · Part 8 · Part 11
ASIL capability
An item’s or element’s ability to meet assumed safety requirements at a stated ASIL, including relevant random hardware failure targets.
For exampleA component supplier states ASIL capability together with assumptions that its customer must satisfy.
A useful distinction
Capability is conditional; a component label does not establish the safety of the integrated item.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.2
Part 1 · Part 9
ASIL decomposition
Allocation of redundant safety requirements serving the same safety goal to sufficiently independent elements, allowing lower ASILs for those allocated requirements under the decomposition rules.
For exampleTwo independent paths implement decomposed requirements; the analysis justifies their independence.
A useful distinction
It does not lower the safety goal’s ASIL or remove the random hardware failure requirements.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.3
Part 1 · Part 2
Assessment
Examination of whether the characteristics of an item or element achieve the applicable functional safety objectives.
For exampleAn assessor evaluates the safety case and supporting evidence before release.
A useful distinction
An assessment judges achieved functional safety; an audit examines implementation of processes.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.4
Part 1 · Part 2
Audit
Examination of how the required processes are implemented and whether they meet their process objectives.
For exampleAn auditor samples change records to check that the planned change process was actually followed.
A useful distinction
A process audit is not the same as assessing the item’s achieved functional safety.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.5
Part 1 · Part 5 · Part 11AEC
Automotive Electronics Council
The industry organization named in commonly used automotive component qualification documents.
For exampleA component data sheet identifies an AEC qualification reference.
A useful distinction
Component qualification does not by itself demonstrate an item’s functional safety or ASIL capability.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1 · Part 2 · Part 3 · Part 4 · Part 5 · Part 6 · Part 8 · Part 9ASIL
Automotive safety integrity level
One of four integrity levels, A to D, used to determine the required safety rigor; D has the most stringent requirements.
For exampleA hazardous event is classified and a safety goal receives the resulting ASIL.
A useful distinction
ASIL is not a product quality grade or a direct failure probability. QM is not a fifth ASIL.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.6
This term also appears in 24 training topics. Search your assigned training to put it into practice.
Part 1
Availability
Ability to provide the required function when it is requested, under stated conditions over the intended lifetime.
For exampleA backup supply allows an essential control function to remain available after a supply fault.
A useful distinction
Availability alone does not establish safety; an available function can still behave dangerously.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.7
Part 1 · Part 5 · Part 11BFR
Base failure rate
A starting hardware failure rate used in an analysis for specified application conditions.
For exampleAn analyst selects a resistor failure rate and documents the temperature and operating assumptions.
A useful distinction
A catalogue number without its mission profile and assumptions is not an application-specific justification.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.8
Part 1 · Part 2 · Part 3
Base vehicle
A truck or bus vehicle configuration before a bodybuilder adds its equipment.
For exampleA chassis cab is delivered before a crane body is installed.
A useful distinction
The complete vehicle includes the subsequently installed bodybuilder equipment.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.9
Part 1 · Part 2 · Part 3 · Part 4 · Part 5 · Part 6 · Part 7 · Part 8 · Part 9
Baseline
An approved, identified set of versions of work products, items or elements used as the basis for controlled further work.
For exampleA review cites the approved requirements and design versions used for its conclusion.
A useful distinction
A file called latest is not a controlled baseline. Evidence baseline and artifact baseline describe the evidence or artifacts being fixed.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.10
This term also appears in 89 training topics. Search your assigned training to put it into practice.
Part 1 · Part 2BB
Bodybuilder
An organization that installs a body or other equipment on a base vehicle.
For exampleA company adds a tipper body to a truck chassis.
A useful distinction
It is a vehicle integration role, not a general term for every component supplier.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.11
Part 1 · Part 2 · Part 3
Bodybuilder equipment
The body, machine or cargo-carrying equipment added to a base vehicle.
For exampleA refuse-compactor mechanism is integrated with a truck.
A useful distinction
Its interfaces can affect vehicle safety even though it was not part of the base vehicle.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.12
Part 1 · Part 6
Branch coverage
The proportion of control-flow branches exercised by a set of tests.
For exampleTests exercise both outcomes of an if statement.
A useful distinction
Executing every statement does not necessarily execute every branch.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.13
Part 1 · Part 5 · Part 11BIST
Built-in self-test
A test function built into hardware or software to check selected parts of its own operation.
For exampleStartup logic tests a memory block before normal operation.
A useful distinction
A BIST name does not establish its coverage, execution interval or ability to detect every fault.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1
Bus
A motor vehicle for people and their luggage with more than nine seats, including the driver’s seat.
For exampleA scheduled passenger bus is within this vehicle category.
A useful distinction
This vocabulary meaning is a road vehicle; CAN bus refers to a communication network.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.14
Part 1 · Part 6
Calibration data
Software parameter values applied after the software has been built.
For exampleA released controller receives a vehicle-specific sensor calibration.
A useful distinction
Configuration data can control what is built; calibration data sets values after the build.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.15
Part 1 · Part 8
Candidate
An existing item or element being considered for a proven-in-use argument, with sufficiently comparable definition and conditions of use.
For exampleA previously deployed controller is evaluated as a proven-in-use candidate for another vehicle.
A useful distinction
A candidate is only proposed for the argument; its operational history does not automatically justify reuse.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.16
Part 1 · Part 9
Cascading failure
A failure of one element that causes a failure of another element.
For exampleA failed supply produces a voltage that damages a connected sensor.
A useful distinction
A common cause directly affects several elements; a cascade propagates from one element to another.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.17
Part 1 · Part 5 · Part 6 · Part 11CPU
Central processing unit
The processor function that executes instructions and controls computation.
For exampleAn ECU’s CPU executes the control software.
A useful distinction
Two CPU cores do not automatically provide independent safety channels.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 2 · Part 6 · Part 7 · Part 8
Change management
The process for requesting, analysing, deciding, implementing and verifying changes to safety-related work throughout the lifecycle.
For exampleBefore changing a sensor, the team evaluates affected assumptions, requirements, interfaces and tests, then records the decision and results.
A useful distinction
Approval of a change request is not proof that implementation and verification are complete.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-8:2018 — Supporting processes · 8.1; 8.4.1–8.4.5
Part 1 · Part 8 · Part 10COTS
Commercial off-the-shelf
A product available commercially for general use rather than developed specifically for one customer’s project.
For exampleA project selects a commercially available software component.
A useful distinction
Off-the-shelf availability does not remove the need to justify suitability, assumptions and integration.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Abbreviated terms · 4
Part 1 · Part 9CCF
Common cause failure
Failures of two or more elements caused directly by one event or root cause.
For exampleA shared supply disturbance disables both redundant channels.
A useful distinction
Different channel designs can still share a power supply or environment and therefore a common cause.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.18
Part 1 · Part 9CMF
Common mode failure
A common cause failure in which the affected elements fail in the same manner.
For exampleA shared interference source drives two sensor readings high.
A useful distinction
Common mode describes the shared failure manner; common cause describes the shared origin.
Further reading
Plain-language teaching explanation. For project decisions, use the applicable standard and your organization’s safety process.
- ISO 26262-1:2018 — Vocabulary · 3.19