This best practice recommends a bottom-up approach, enabling a better understanding of local environmental conditions, roadway geometries, physical infrastructure, zones and behavior of other road users. (SAE International)

New best practice establishes commonly defined terms, conceptual framework for ADS ODD

The Automated Vehicle Safety Consortium (AVSC) recently released a new best practice for automated driving systems (ADS) developers.

The Automated Vehicle Safety Consortium (AVSC), an industry program of SAE Industry Technologies Consortia (SAE ITC), released a new best practice in April 2020 developed for automated driving systems (ADS) developers and manufacturers responsible for defining their ADS Operational Design Domain (ODD).

The Best Practice for Describing an Operational Design Domain: Conceptual Framework and Lexicon document establishes common terms and a framework in which to apply them. Where applicable, labels, definitions and measurement ranges are provided to promote consistent communication and to help ensure that users’ ADS expectations are aligned with capabilities.

The ODD generally defines when, where, and under what conditions an automated vehicle is designed to operate, or, specifically, those conditions in which it can't operate. “Guidance to date has been very general. The ODD is described by manufacturers for the ADS product that they put on the roads,” explained Edward Straub, executive director of AVSC. “This practice is a first step toward standardizing the way manufacturers describe their systems and reducing confusion in the public.”

“With this new best practice, we try to address the potential for confusion by doing two things: first, publishing a conceptual framework manufacturers could consistently follow when describing their ODD, and secondly, by creating an initial version of a lexicon for some of those variables that manufacturers could use when they create that description,” Straub shared with Automotive Engineering. “With a shared set of definitions, transportation agencies and industry can better communicate with each other – and the public – about ADS deployments, tests, and operations.”

The document provides a framework and a common vocabulary. “Again, it's not defining ODD by any stretch. That's up to the manufacturer. Following the framework, more standardized descriptions should be created which will streamline the communication process between industry and public agencies,” he explained. The vehicles may be measuring different things, which again will be up to the manufacturer, but the descriptions will be similar, and it will help the using-public calibrate their expectations around the performance of these vehicles.

Straub noted that the framework really begins with identification of the road and route network, mapping and defining that in detail. Moving on then to characterizing the fixed infrastructure around it and then describing and characterizing the operational constraints, which can be captured in a human-understandable narrative.

“We call that a bottom-up approach,” he noted. “Bottom-up meaning you're starting right at the ground, right at the road network and saying this is the geography that an ADS will operate in, these are the very specific roads that they’ll operate on. And that's different from some of the other conversations around ODD that happened earlier – and sometimes still happen – where people are expecting ADS to operate on a certain type of road.”

With a mission to publish best practices that will inform and lead to industry-wide standards advancing the safe deployment of ADSs, the AVSC is working closely with the SAE International Standards Committees and discussing the introduction of the content of the Best Practice for Describing an Operational Design Domain: Conceptual Framework and Lexicon to them.

“Our hope and plans are that the concepts in our work is integrated into open-industry SAE J-standards. These discussions are happening now with AVSC’s first best practice In-Vehicle Fallback Test Driver Selection, Training, and Oversight Procedures for Automated Vehicles Under Test and we are pleased about it.”

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