Abstract
To address limitations in existing passive safety standards that constrain new intelligent vehicle technologies, and based on revisions by international standards organizations and U.S. standards bodies, this paper proposes an evaluation framework and a development roadmap for passive safety standards for intelligent vehicles in China. A national mandatory standard is used as an example to support suitability assessment and future revisions.
1 Introduction
With the rise of artificial intelligence and next-generation information and communication technologies, vehicles are accelerating toward intelligence as one of the primary platforms for integrating new technologies. Intelligent vehicles have become a strategic direction and competitive focus for the global automotive industry [1-4].
To prevent current standards from constraining new technologies, and drawing on revision principles and methods from international standards organizations and U.S. standards bodies, this study develops an evaluation framework and a roadmap for China’s intelligent vehicle passive safety standards, and conducts preliminary exploration of revisions to passive safety standards.
2 International progress on passive safety standards for intelligent vehicles
2.1 U.S. NHTSA: principles and scope of passive safety standard revisions
Since 2016, the United States has systematically reviewed existing passive safety standards to address conflicts and impacts arising from the development of intelligent vehicle technologies [5]. The National Highway Traffic Safety Administration (NHTSA) published a testable case and scenario framework for automated driving systems on September 28, 2018 [6], and issued an Advance Notice of Proposed Rulemaking (ANPRM) on May 28, 2019 to address potential impacts of future intelligent vehicle development on crash safety performance [7-8]. To address novel vehicle designs, especially non-passenger vehicles or vehicles with significant changes to driver position or controls, NHTSA issued a proposed rule on March 30, 2020 to amend several crashworthiness regulations and clarify safety requirements for motor vehicles without driver controls [9]. On January 13, 2021, NHTSA released a revised proposal intended to remove significant, unnecessary regulatory barriers to production, sale, and use of future intelligent vehicles [10-11]. On March 10, 2022, NHTSA published a final rule updating Federal Motor Vehicle Safety Standards for occupant protection to ensure safety for occupants of automated vehicles.
2.1.1 Revision principles
The revision principles included: maintaining occupant protection performance equivalent to conventional vehicles; removing regulatory provisions that are unnecessary for intelligent vehicle development; ensuring revised requirements facilitate vehicles equipped with intelligent technologies without changing requirements for non-intelligent vehicles; and keeping changes technology-neutral in line with the U.S. Department of Transportation guidance "Preparing for the Future of Transportation: Automated Vehicles 3.0," so that revisions neither favor active safety nor passive safety, while better accommodating some innovative interior designs in FMVSS.
2.1.2 Preconditions for revisions
a. Assume seat layouts for intelligent vehicles are the same as for conventional vehicles; other seat layouts require further study.
b. Revised crash safety requirements address cargo-only vehicles (no or few passengers) without addressing compatibility issues.
c. Revisions are limited to FMVSS Series 200 and do not apply to Series 300 standards. Requirements related to signaling devices and warnings were not revised because impacts extend beyond Series 200 and remain under further study. Changes to airbag suppression signal devices were planned for separate future notices.
2.1.3 Scope of revisions
Revisions address scenarios with no driver seating but multiple front-row occupant positions. For front-row airbag indicators and suppression devices, separate indicators visible for each front seating position were recommended.
Requirements for seat belts on medium buses (curb weight 4,536–11,793 kg) and school buses (curb weight above 4,536 kg) were revised; for driverless intelligent vehicles, front-row seat requirements were recommended to match driver seat requirements.
When vehicles have no steering wheel or steering controls, FMVSS 203 and FMVSS 204 would not apply for assessment of intelligent vehicles. It was suggested that occupant protection standards not apply to cargo-only vehicles by modifying applicability to indicate the standards apply only to trucks with a driver.
NHTSA proposed revisions to FMVSS 201, 205, 206, 207, 208, 214, 216, and 226.
2.2 WP.29 passive safety working party: scope of revisions
At the 71st session of the Working Party on Passive Safety (GRSP) under the World Forum for the Harmonization of Vehicle Regulations (WP.29) on May 10, 2022, a study group was established to coordinate passive safety standards with intelligent vehicle functions. The group studies compatibility issues between current ECE regulations and Global Technical Regulations (GTR) on passive safety and future intelligent vehicle technologies to support reasonable development of passive safety performance for intelligent vehicles [12].
3 Progress on passive safety standards for intelligent vehicles in China
3.1 Status of intelligent vehicle standards and mandatory passive safety standards
In recent years, production of intelligent vehicles in China has grown rapidly, and technologies combining active and passive safety have advanced. Planning and development of vehicle safety technologies have driven the development and updating of active and passive safety standards [13-15].
Intelligent vehicle standards are primarily organized by the National Technical Committee of Auto Standardization, SAC/TC114. Standards are categorized into foundational, general specifications, products and technical applications, resource management and information services, and related standards. To date, 12 intelligent vehicle standards have been published, and 26 standards are under study, approved for project, or pending publication. These standards mainly define technical functions and performance for functional safety, information security, network security, and human-machine interaction, and do not specify occupant protection performance requirements.
Passive safety standards are mainly organized by the National Technical Committee of Auto Standardization Subcommittee on Vehicle Collision Testing and Protection, SAC/TC114/SC33. Currently, 96 national mandatory automotive standards have been approved, 28 of which are passive safety standards, accounting for 29%. These standards focus on vehicle and component performance in collisions and occupant protection, but have not addressed effects of new intelligent vehicle functions and components on occupant injury.
Active safety functions and components in intelligent vehicles, such as automatic emergency braking, can significantly change occupant posture and position during a crash, rendering traditional passive safety systems insufficient to minimize occupant injury. Additionally, future driverless scenarios and changes in occupant seating posture may create technical conflicts with current standards. To avoid limiting technological progress, a systematic technical scan of current national standards is necessary to propose corresponding revisions and support orderly industry development.
3.2 Evaluation framework for China’s intelligent vehicle passive safety standards
Considering current intelligent vehicle technology trends and the revision processes of national and international standards organizations, and based on standards content and revision directions, an initial framework for China’s intelligent vehicle passive safety standards has been developed. The framework aims to facilitate vehicles equipped with intelligent technologies without changing requirements for non-intelligent vehicles.
3.2.1 Preconditions
a. Intelligent commercial vehicles are assumed to be unoccupied;
b. Intelligent passenger vehicles are assumed to be driverless;
c. Intelligent vehicles may have no steering wheel or may have a retractable steering wheel;
d. Changes to interior layouts and seating arrangements are expected.
3.2.2 Principles
Conventional vehicles and intelligent vehicles will coexist in traffic and must provide equivalent occupant protection. Revisions should support intelligent vehicle technologies and accommodate new interior structures or arrangements without restricting innovation or altering requirements for conventional vehicles.
3.2.3 Content of the framework
For coexistence of intelligent and conventional vehicles, standards should be revised as follows:
a. Modify applicability to distinguish vehicle types and whether they are intelligent vehicles;
b. Revise terminology and test procedures to account for presence or absence of a driver, steering controls, and new interior layouts;
c. Update seat arrangement and occupant protection requirements to address changes in front-row airbag and seat belt positioning;
d. Revise airbag and seat belt warning device requirements to reflect changes in occupant positions;
e. Adapt component and vehicle crash standards to new interior and seating arrangements;
f. Revise test methods and procedures for standards to cover scenarios where active safety systems intervene.
3.3 Development roadmap for China’s passive safety standards
According to intelligent vehicle development planning, Highly Autonomous driving (HA) technologies are expected to enter the market around 2025, with HA-level intelligent connected vehicles widely used on highways and deployed at scale on some urban roads by 2030. After 2035, HA and Fully Autonomous driving (FA) vehicles will have networked collaborative decision and control capabilities, and highly autonomous vehicles will operate widely across China.
The overall roadmap for development of the passive safety standards system is shown in Figure 1. Based on achievable technologies, and addressing passenger cars, freight vehicles, and buses, the roadmap establishes technical architectures for whole vehicles and components. Key research areas include vehicle crash test techniques when active safety systems intervene, occupant protection evaluation for new interiors and seating postures, and component crash tests for new collision modes.
3.4 Case analysis: a mandatory passive safety standard
By analyzing technological trends for each development stage of intelligent vehicles, relevant safety scenarios, and potential future crash conditions, the suitability of existing standards can be assessed to determine whether standards should be repealed, revised, strengthened, or added.
4 Conclusion
This study analyzed the focus areas of intelligent vehicle standards and national mandatory passive safety standards in China. Intelligent vehicle standards mainly specify technical functions and performance for functional safety, information security, network security, and human-machine interaction, but do not set occupant protection performance requirements. National mandatory passive safety standards focus on vehicle and component performance in collisions and occupant protection, but do not address effects of new intelligent vehicle functions and components on occupant injury. To support new technologies and genuinely minimize occupant injury, this paper offers preliminary proposals for drafting and revising passive safety standards for future intelligent vehicles. Drawing on revision principles and methods from international standards organizations and U.S. standards bodies, it proposes an evaluation framework and a development roadmap for passive safety standards in China.
