Quite often I hear the same questions from various automotive companies.
Is it legally required for the automotive products to comply with functional safety standards/requirements? Which standards/regulations should I use to demonstrate compliance with functional safety?
In this article I will answer these questions. I will offer you a brief overview of existing US and EU regulations that are related to vehicle and functional safety, and also, we will make a dive into the landscape of automotive functional safety standards.
EU Vehicle Safety Legislation
Let’s first try to figure out if demonstrating functional safety for your products is mandatory based on the EU and US regulations.
If we take a look at the EU legislation, we will notice that for the automotive industry there is a Regulation (EU) 2019/2144 of the European Parliament which applies to vehicles of categories M, N and O, and to systems, components and separate technical units designed and constructed for such vehicles. This regulation establishes requirements
“…for the type-approval of vehicles, and of systems, components and separate technical units designed and constructed for vehicles, with regard to their general characteristics and safety, and to the protection and safety of vehicle occupants and vulnerable road users”.
So basically the regulation contains requirements on what a vehicle type-approval looks like in order to make sure the vehicle is safe (note that the regulation talks about general safety only, not specifically a functional safety). Article 4.2 of this regulation says:
“Type-approval in accordance with the UN Regulations listed in Annex I shall be considered as EU type-approval in accordance with the requirements of this Regulation and of the delegated acts and implementing acts adopted pursuant to it”.
You can interpret it in the following way: “To prove your vehicle is safe you need to pass a type-approval procedure. The type-approval procedure shall be based on the regulations of the United Nations Economic Commission for Europe (UN ECE)”. You can find these regulations on the UN ECE official website. There are 150+ regulations there and each of them defines requirements and test scenarios for vehicle systems (e.g., braking system or steering system) and engineering domains (e.g., cybersecurity). Now if we carefully read UN ECE regulations, we will notice that several of them directly mention functional safety compliance as one of the mandatory requirements. Here is the list of these regulations.
- Regulation №13 concerning the approval of vehicles of categories M, N and O (except for passenger cars) with regard to braking (see Annex 18);
- Regulation №13-H concerning the approval of passenger cars with regard to braking (see Annex 8);
- Regulation №46 concerning the approval of devices for indirect vision and of motor vehicles with regard to the installation of these devices (see Annex 12);
- Regulation №79 concerning the approval of vehicles with regard to steering equipment (see Annex 6);
- Regulation №100 concerning the approval of vehicles with regard to specific requirements for the electric power train (see Annexes 8E-8I);
- Regulation №123 concerning the approval of adaptive front-lighting systems (AFS) for motor vehicles (see Section 2.2.2.1);
- Regulation №131 concerning the approval of motor vehicles with regard to the Advanced Emergency Braking Systems (AEBS) (see Annex 4);
- Regulation №139 concerning the approval of passenger cars with regard to Brake Assist Systems (BAS) (see Section 5.5);
- Regulation №140 concerning the approval of passenger cars with regard to Electronic Stability Control (ESC) Systems (see Section 5.5);
- Regulation №152 concerning the approval of motor vehicles with regard to the Advanced Emergency Braking System (AEBS) for M1 and N1 vehicles (see Annex 3);
- Regulation №156 concerning the approval of vehicles with regards to software update and software updates management system (see Section 7.1.4.1);
- Regulation №157 concerning the approval of vehicles with regard to Automated Lane Keeping Systems (see Annex 4).
So, in the EU it is legally required to prove functional safety for at least 10 vehicle systems (listed above). Before we look at the US legislation, I think it is important to mention that safety for the automated vehicles is also mentioned in the Regulation 2019/2144, which says that automated vehicles of any automation level shall comply with the technical specifications set out in the implementing acts related to:
- systems to replace the driver’s control of the vehicle, including signaling, steering, accelerating and braking;
- systems to provide the vehicle with real-time information on the state of the vehicle and the surrounding area;
- driver availability monitoring systems;
- event data recorders for automated vehicles;
- harmonized format for the exchange of data for instance for multi-brand vehicle platooning;
- systems to provide safety information to other road users.
US Vehicle Safety Legislation
Back in 1966 the US adopted a National Traffic and Motor Vehicle Safety Act, U.S. legislation that requires automobile manufacturers to institute safety standards to protect the public from unreasonable risk of accidents occurring as a result of the design, construction, or operation of automobiles.
To formalize the regulatory requirements for the automobile manufacturers the US National Highway Traffic Safety Administration (NHTSA) has released the Federal Motor Vehicle Safety Standards (FMVSS) for motor vehicles and motor vehicle equipment that are legally a part of the Code of Federal Regulations (CFR) — primary US regulatory law. FMVSS can be found in the CFR Title 49, Subpart B, Chapter V, Part 571. However, neither FMVSS, nor other CFR Titles mention functional safety anywhere in their text. This implies functional safety is not legally required in the US, at least from the regulatory law perspective.
It is worth noting that NHTSA and National Transportation Safety Board (NTSB) release multiple reports and recommendations every year that encourage automobile manufacturers to ensure functional safety of their products. But these reports and recommendations are not binding for the manufacturers.
An interesting fact is that some of the US states have local acts and laws concerning vehicle safety, which complement the CFR. For instance, California has its own Autonomous Vehicles Regulation which mentions that AV manufacturers that have publicly disclosed an assessment demonstrating their approaches to achieving safety shall provide the department (Department of Motor Vehicles) with a copy of that assessment. However, these state regulations also do not obligate manufacturers to demonstrate functional safety of their products.
Functional Safety Standards for Road Vehicles
At this point we’ve figured out that only EU regulations mandate demonstrating functional safety for the automotive products, whereas the US state and federal authorities only recommend that. Here is a diagram that explains this idea.

Now let me show you the landscape of functional safety standards. The diagram below shows the primary functional safety standard IEC 61508 in the center (its first edition was released back in 1998) and industry-specific functional safety standards around it. All these industry-specific standards are not expansions of the IEC 61508 or its altered versions, but rather standalone standards that have inherited the spirit of IEC 61508 (e.g., how functional safety shall be addressed depending on the industry specifics).

When we speak about functional safety standards for road vehicle applications, the main standard here is ISO 26262. This standard is the adaptation of IEC 61508 to address the needs of electrical and/or electronic (E/E) systems within road vehicles (e.g., controllers, sensors etc). There is a great intro to this standard in the first part that says the following.
This document describes a framework for functional safety to assist the development of safety-related E/E systems. This framework is intended to be used to integrate functional safety activities into a company-specific development framework. Some requirements have a clear technical focus to implement functional safety into a product; others address the development process and can therefore be seen as process requirements in order to demonstrate the capability of an organization with respect to functional safety.
In other words, the standard provides an idea of how the safety-related systems shall be developed in the automotive industry both from the process and technical perspectives.
The standard, however, only covers functional safety from the systematic SW and HW failures, and random HW failures. But it doesn’t elaborate on the functional safety requirements associated with the hazardous behavior of intended functions (e.g., if a vehicle function performs erroneously in a specific operational environment, though there are no systematic or random failures). One of the examples here may be an incorrect operation of an automated vehicle due to limitations of sensor capabilities in a foggy environment. The sensor itself works with no faults, but the overall automated vehicle’s operation becomes incorrect and potentially hazardous as specifically in the foggy environment the sensor is not capable of performing its functions correctly. For this purposes the other standard has been developed — ISO 21448 “Safety of the Intended Functionality”, and this addresses not only the AV’s functional insufficiencies, but also a reasonably foreseeable misuse of some of the automotive systems (e.g. HMI) by a driver.
Together both ISO 26262 and ISO 21448 cover the majority of the functional safety aspects of motor vehicles and AVs. To close the gaps related to the cybersecurity and AI impact on the functional safety two more standards were developed:
- ISO 8800 Road Vehicles — Safety and artificial intelligence;
- ISO TS 5083 Road vehicles — Safety for automated driving systems — Design, verification and validation.

Other supplementary standards may be used by manufacturers to aid achieving functional safety e.g.,
- UL 4600 Evaluation of Autonomous Products;
- SAE Automated Vehicle Safety Consortium (AVSC) Best Practices, etc.
Conclusion
With all we know now, let’s answer the questions we have set at the beginning of this post.
- Q: Is it legally required for the automotive products to comply with functional safety standards/requirements?
A: Yes, if you are in the EU. You are then obligated to demonstrate functional safety for certain systems of a vehicle. If you are in the US, you may need to demonstrate functional safety compliance if that is explicitly required by the state or federal authority (otherwise, functional safety compliance for the motor vehicles in the US is only recommended). - Q: Which standards/regulations should I use to demonstrate compliance with functional safety?
A: Normally this will be ISO 26262. But if you design AV or HMI systems, other functional safety standards may also apply (e.g., ISO 21448). This is not mandatory though to demonstrate compliance with ISO 26262 specifically. One may choose any other standard for this purpose (even self-made). However, the best way is to follow the proven-in-use and widely adopted ISO 26262 and other functional safety standards.
Reference: https://islambabaev.com/automotive-functional-safety-landscape-in-10-minutes-76b5a088abbc
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