GB/T 44433-2024Performance requirements and test methods for intelligent speed limiting systems of motor vehicles (English PDF)

1 Scope

GB/T 44433-2024 sets the performance requirements and test methods for intelligent speed limiting systems: the function that reads the speed limit from traffic signs and from map data and either warns the driver or limits the vehicle to it. It is mandatory on new vehicles in Europe and it is being adopted in China, which is what this standard exists for. The document specifies the functional requirements, the accuracy with which the applicable speed limit must be determined and the handling of conditional limits, of variable message signs and of conflicting sources, the warning strategy and its escalation, the requirements on the speed limitation function itself and on the driver's ability to override it, the behaviour on failure and where the limit cannot be determined, and the human-machine interface. It then gives the test methods, the road and track scenarios covering sign recognition, map-based determination, the transition between limits and the override, and the pass criteria for each. For a carmaker or a supplier bringing such a system to China, this is the governing text.

This document specifies the general requirements and performance requirements for intelligent speed limit system of vehicles and describes the corresponding test methods. This document applies to category-M and category-N vehicles equipped with intelligent speed limit system. The technical requirements and test methods related to the intelligent speed limit control function applies to category-M1 vehicles, and as a reference to other types of vehicles.

Note: Where no confusion is caused, the "intelligent speed limit system of vehicles" in this document is referred to as the "system".

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB 5768.2-2022, Road traffic signs and markings - Part 2: Road traffic signs

GB 5768.5, Road traffic signs and markings - Part 5: Speed limit

GB 21670, Technical requirements and testing methods for passenger car braking systems

GB 34660, Road vehicles - Requirements and test methods of electromagnetic compatibility

GB/T 39263, Road vehicles - Advanced driver assistance systems - Terms and definitions

3 Terms and definitions

For the purpose of this document, the following terms and definitions, as well as those given in GB/T 39263, apply.

3.1 After the system obtains the road speed limit information and determines that this information is valid, the shortest driving distance within which the vehicle continues to display the speed limit information in this lane.

3.4 stabilized speed The average driving speed of the vehicle when it is in a stable driving state under the intelligent speed limit control function.

3.5 control activated The system meets the technical conditions specified by the manufacturer and performs intelligent speed limit control.

3.6 intervention The behavior that the driver actively influences the intelligent speed limit system to perform the speed limit control function in an effective manner specified by the manufacturer.

6 Test methods

6.1 Test environment conditions The test environment conditions shall meet the following requirements: -- Horizontal visibility greater than 1 000 m; -- Ambient temperature at -20 °C ~ 45 °C; -- Average wind speed at least 1 m above the ground not more than 5 m/s, and the maximum wind speed not more than 10 m/s; -- Test carried out on a level, dry concrete or asphalt pavement with good adhesion; -- Speed limit sign located on the side of the road or above the lane and meeting the requirements of

5.36 in GB 5768.2-2022; -- Size, shape, color and installation of speed limit signs meeting the requirements of GB 5768.2-2022 and GB 5768.5.

Appendix A

(Normative) Functional safety requirements for systems with intelligent speed limit control function A.1 General This Appendix does not target the nominal performance of the system, nor does it serve as specific guidance for the functional safety development of the system. Instead, it specifies the methods to be followed in the design process and the information to be available during system verification and validation to demonstrate that the system can achieve the functional concept and functional safety concept in both normal operation and failure conditions and meet all applicable performance requirements specified in this document. A.2 Documentation A.2.1 Requirements There shall be documentation describing the functional concept of the system, the functional safety concept, safety strategy, development process and methods developed to achieve the safety goals, so as to demonstrate that the system:

a) can achieve the functional concept and functional safety concept in both non- failure and failure conditions through design;

b) meets the performance requirements specified in this document under non- failure and failure conditions;

c) development processes and methods are applicable. A.2.2 System description A.2.2.1 The functional concept of the system, i.e., the purpose and functional description list, shall be described. A.2.2.2 The scope of the system shall be defined, its subsystems and elements shall be clearly defined, and the external systems or elements with which it interacts shall be identified. A.2.2.3 The operating conditions and constraints of the system shall be defined, and the limits of the effective working range shall be stated for the corresponding system functions. A.2.3 System layout and schematic diagram A.2.3.1 System component list A component list shall be provided, which shall include all component elements of the system and shall also list other vehicle systems required to achieve the relevant control functions. A system layout and schematic diagram shall be provided based on these component elements, which shall clearly show the component distribution and interconnection. A.2.3.2 Element function The functions of each element of the system shall be summarized and the signal connections between the element and other elements or other systems in the vehicle shall be shown. A labeled block diagram or other schematic diagrams may be used, or the illustration may be aided by a chart. A.2.3.3 Interconnection The interconnections among the electronic transmission chain, hydraulic transmission chain and mechanical connection devices within the system shall be respectively explained using circuit diagrams, piping diagrams and layout diagrams. A.2.3.4 Signal flow, operating data and priorities There shall be a clear correspondence between the transmission chains, signals and operating data between elements. Priority shall be established for signals and operational data within multiple data channels if the priority affects performance or safety as described in this document. A.2.3.5 Element identification Each element shall be clearly and unambiguously identifiable (e.g., identification of hardware, identification of software content, or software output) and provided with a corresponding description. When an element or a single processor that integrates multiple functions appears multiple times in a block diagram, only one hardware identification marking is used for clarity and ease of explanation. Identification markings shall be used to confirm that the device supplied is consistent with the corresponding documentation. The identification marking shall clearly indicate the versions of the hardware and software. If the functions described in this document are changed due to version changes, the identification marking shall be changed accordingly. A.2.4 Hazard analysis and risk assessment The functional failures of the system shall be analyzed and categorized. A.2.6.1 The above documentation shall be supported by a safety analysis that provides an overall description of the effective identification and handling of hazards and failure groups that affect vehicle motion control and safety goals. Safety analysis shall include but is not limited to the following contents.

a) Safety analysis at the vehicle level, confirming the following: 1) interaction with other vehicle systems; 2) abnormal functional manifestations; 3) safety risks under non-failure conditions.

b) System-level safety analysis may adopt failure mode and effect analysis (FMEA), fault tree analysis (FTA) or other similar methods suitable for system safety analysis.