INTRODUCTION

What is an ODD?

The Operational Design Domain (ODD) describes the conditions under which an automated driving system (ADS) operated vehicle is designed to function. The ODD could include, but is not limited to, aspects of the environmental, geography, time-of-day, and the presence or absence of certain traffic or roadway characteristics.  In order to enhance collaboration and communication between manufacturers and developers, transportation agencies, and other stakeholders, a consistent way to describe an ADS’s ODD is needed.

INTRODUCTION

What is an ODD?

The Operational Design Domain (ODD) describes the conditions under which an automated driving system (ADS) operated vehicle is designed to function. The ODD could include, but is not limited to, aspects of the environmental, geography, time-of-day, and the presence or absence of certain traffic or roadway characteristics.  In order to enhance collaboration and communication between manufacturers and developers, transportation agencies, and other stakeholders, a consistent way to describe an ADS’s ODD is needed.

Why is a common vernacular to describe ODDs necessary?

An ADS-operated vehicle’s ODD is defined by the manufacturer based on numerous factors. Research is underway at other organizations to define and organize ODD elements into taxonomies and other relational constructs. In order to enhance collaboration and communication between manufacturers and developers and transportation agencies, common terms and consistent frameworks are needed. 

The conceptual framework presented by AVSC establishes a lexicon that can be used consistently by ADS developers and manufacturers responsible for defining their ADS ODD. A common framework and lexicon will reduce confusion, align expectations, and therefore build public trust, acceptance, and confidence.

SCOPE

The guidance in this document is intended for:

• The technical community (e.g. manufacturers and developers)
• Public agencies (e.g. transportation agencies)
• Infrastructure owner-operators
• The public

This document, Best Practice for Describing an Operational Design Domain: Conceptual Framework and Lexicon is a critical first step. It offers a conceptual framework for manufacturers and developers to use when communicating with public agencies and the general public about their ADS’s ODD. It also details a list of potential variables with definitions that manufacturers and developers might use to describe certain aspects of the ODDs of their ADS-operated vehicles. 

It was developed with fleet-managed, SAE Level 4 vehicles in mind — i.e. vehicles requiring no human intervention to operate within their ODD.  These vehicles are NOT privately owned.

CONCEPTUAL FRAMEWORK

A bottom-up approach

The conceptual framework describes a bottom-up approach for defining an ODD that enables better understanding of conditions, roadway geometries, road users, and infrastructure. It is easily modified, and can be identified via specific, mapped routes that meet criteria. 

The section also covers methods of route identification, fixed route characterization, and identifying operational constraints.

Narrative

Through this framework, developers can formulate a narrative that allows for better communication across all stakeholders, including the public, describing where an ADS will operate, what its capabilities are, and what conditions affect it. Consistent communications increase public confidence.

LEXICON

The best practice introduces terminology and categories that can be used by manufacturers when describing an ADS’s ODD.  

• Weather-related environmental conditions
  • Temperature
  • Precipitation types
  • Haze
  • Sky condition
  • Illuminance (Lux)
  • Sun angle
  • Wind
• Road surface conditions
  • State of repair
  • Quality of road markings
  • Road surface obscurants
  • Roadway infrastructure
  • Road Network
  • Route Network
  • Sight Distance
  • Curbs
  • Shoulders
  • Berms
  • Surface crowning
  • Traffic control devices
  • Etc.
• Superelevation
• Curvature
• Ramps
• Intersections
• Road Design Elements
  • Lanes
  • Mixed Use
  • Etc.
• Operational Constraints
  • Rush Hour
  • Intended Operational Times
  • Zones
• Road Users
• Non-Static Roadside Objects
• Connectivity

Note: This is an abbreviated list of terms that are explored in the full Best Practice document.

SUMMARY

By adopting the same shared terminology and definitions, operators, transportation agencies, and the general public can reach a common understanding of ADS operating conditions. The conceptual framework and lexicon introduced in this best practice is a critical first step in this effort. Follow-on research and discussion in an open forum will expand this lexicon.