Automated Driving Systems: The PAS 1883:2020 Standard Explained

What is PAS 1883:2020 about?

This document is one in a series commissioned by The Centre for Connected and Autonomous Vehicles (CCAV) to support the development of CAVs in the UK and help shape the future of international CAV standards. PAS 1883:2020 deals with requirements for an ODD taxonomy.

Who is PAS 1883:2020 for?

Trialling organizations developing safety cases for automated vehicle trials and testing.

Manufacturers of level 3 and level 4 ADS to define the operating capability.

Insurers, regulators, service providers and national, local and regional government to enable them to understand possible ADS deployments and capabilities.

Why should you use PAS 1883:2020?

It provides requirements for the minimum hierarchical taxonomy for specifying an Operational Design Domain (ODD) to enable the safe deployment of an automated driving system (ADS).

The ODD comprises the static and dynamic attributes within which an ADS is designed to function safely. This PAS is applicable to Level 3 and Level 4 ADS. Its use will:

accelerate innovation;
improve the efficiency of development;
help manage risk and increase trust;
support and accelerate the UK’s delivery of safe and secure CAV technologies and services;
showcase the UK’s leadership in this fast evolving and highly technical domain; and
help shape the future of international CAV standards.

Purpose of PAS 1883:2020?

The purpose of PAS 1883:2020 is to facilitate and define a taxonomy for the ODD which is capable of describing, recognizing, and securely enabling operation of the ADS within its ODD. This taxonomy is necessary because ODDs for industry, manufacturers, and suppliers can differ. The PAS defines a minimum set of ODD elements that all can agree upon.

This will enable organizations to define a common categorization of critical hazards and non-critical aspects of infrastructure elements and other road users.

Answers to critical questions concerning the design, development, testing, integration and deployment of future road devices within ODDs may be found in PAS 1883:2020.
The PAS and this accompanying guidance will provide the knowledge base necessary to plan, specify, assess, and execute practical trials, as well as to allow untested systems to be accepted for deployment by providing a standardized and agreed set of ODD elements which may be used throughout the road space.

The PAS provides the know-how to support rapidly and to deploy fully autonomous vehicles on public highways, and go beyond that to support the development, deployment and evolution of mixed-use networks. Network based vehicles will be able to mix with driver-based vehicles on the same roadways, but will require a higher degree of engineering and integration to achieve safer performance.

Key features of PAS 1883:2020?

The PAS provides a clear and unambiguous definition of the ODD, including the following:

The ODD involves the definition of requirements for all operating conditions and environments that can exist on the public highway. These requirements are expressed as a hierarchy of road elements and their attributes, characteristics and capabilities which apply to different aspects of the system, with the top level being the System domain, which relates to the external environment.
The ODD requires the rigor and discipline of analysis and verification of safety requirements during the design phase and maintenance phase of the ADS.
The ODD enables validation of the ADS’s safety-critical behaviors to ensure that protective measures are always engaged at the appropriate time and place on the road to protect against identified hazards.
The PAS provides the following detailed guidance on what it means to specify, define and describe a taxonomy of the ODD:
The taxonomy’s hierarchical structure and the relationships between the elements of the taxonomy.
Consideration of requirements for each element of the taxonomy relating to:
its presence or absence on the road;
its provenance, e.g. the agency or service provider from which it may be obtained;
the restrictions on its use; and
the capabilities/desired characteristics to which the element must conform.
Consideration of the organizational means by which the taxonomy is designed, deployed, managed, maintained and updated.
Consideration of the processes, audits, evaluations and testing against the taxonomy as part of the implementation, operations and maintenance phase of the system.

The result of following the guidance is intended to provide the documentation whereby detailed or complex ODDs are specified, verified, and deployed.

Why is the development, deployment, and evolution of future autonomous vehicles so challenging?

This comes down to the reality that the ODD for a commercial ODD provider may differ significantly from that of the designer of a vehicle-based ADS and the designer of its central controller. There may also be operator-specific ODD elements for the road and vehicle user, but to accommodate this industry-wide there is a requirement to agree at least a minimum set of elements that all parties can accept.

How is the UK’s vehicle-based ADS ODD related to the ODD of the road itself?

The ODD for the road traffic system will be defined by the Department for Transport and Vehicle Services Agency, and will control the operation of the ADS, as well as the trusted party and other road users. The ADS will need to be able to detect the environment in which it wishes to operate, and then map its operating envelope to a particular ODD. This will affect the ADS’s ability to change modes and may depend upon the vehicle’s automation level.

How does PAS 1883:2020 specifically help?

It provides the requirements for the minimum hierarchical taxonomy for specifying an Operational Design Domain (ODD) to enable the safe deployment of an automated driving system (ADS).

The ODD comprises the static and dynamic attributes within which an ADS is designed to function safely. This PAS is applicable to Level 3 and Level 4 ADS.

Its use will: