GB/T 47045-2026Determination method for priority of on-board messages of passenger car (English PDF)

4.1 Overview

The data for the information priority index is collected in accordance with the steps outlined in 4.2~4.6.

4.2 Appointment of examiners

The priority index method requires examiners to coordinate the preparation and analysis of data, and the completion of the report. The responsibilities of the examiners are set forth in 4.7.

Examiners shall be familiar with prioritization methods and processes, possess an understanding of in-vehicle information management content, and have practical experience in the real-vehicle testing and usage of in-vehicle information systems, as well as a foundational understanding of human-machine interaction within information systems.

If the qualifications of the examiner are similar to those of the evaluator, the examiner may participate in the evaluation simultaneously as both an examiner and an evaluator.

4.3 Identifying and integrating information

Examiners shall identify in advance the information that the human-machine interface shall present to the driver. Examiners shall collect this information and submit it to the evaluators.

4.4 Defining driving environments and conditions

4.4.1 General principles

Examiners must define or assist in defining the driving environment and conditions, based on the road environment and traffic conditions that may present information.

When presenting information, it is advisable to define the relevant environmental and situational factors. Particular care shall be taken regarding the presentation of information in situations involving potential hazards. All hazardous situations shall be considered, with the exception of those deemed extremely unlikely to occur. Based on these conditions, the examiner may define one or more scenarios - typically no more than four - for a specific piece of information. In cases where the vehicle is unable to perceive the situation, or where only a single scenario is utilized for a given piece of information, that scenario shall represent a reasonable "worst-case" situation. If the same information is presented under two different scenarios, it shall be treated as two distinct information items for the purpose of evaluation.

NOTE 1.The priority of information related to system faults depends on the vehicle's status (for example, the priority differs depending on whether the vehicle is in the start-up or driving state).

NOTE 2.The information provided to the driver shall depend on the vehicle's ability to perceive or detect various relevant conditions (for example, if the vehicle detects the driver's state of alertness, the driver's alertness level is taken into account when describing the driving scenario).

4.4.2 Factors to consider when formulating driving scenarios

4.4.2.1 General principles

Table 1 lists examples of factors to be considered when formulating driving scenarios;

examiners may refer to Table 1 to define the driving environment and relevant conditions. Examiners may utilize these environmental and situational factors to define driving scenarios. For driving environments and conditions in the examples that cannot be categorized under the candidate factors listed in Table 1, they shall be described under the "Other" category. If a factor serves to define neither the environment nor the conditions, "To be defined" shall be selected in the candidate column.

When clearly describing the driving environment and conditions, evaluators shall consider the factors listed in Table 1 during the rating process.

Table 1 -- Examples of factors to consider when formulating driving scenarios

4.4.2.2 Driving tasks

A driving task involves factors such as travel purpose (e.g., commuting, leisure), time or location within the route (e.g., the relative position between the origin and destination), and the anticipated distance to the next maneuver.

Example. Turning (or merging) shortly (e.g., after traveling 20 m).

4.4.2.3 Road environment

The road environment refers to static factors related to road structure that influence vehicle operation. It shall encompass road type (e.g., highways, urban roads, rural roads), speed limits, the number of lanes, and road width. Furthermore, it shall account for the impact of the surrounding context on driving, including weather conditions (e.g., rain) and the time of day (e.g., morning, daytime, evening).

4.4.2.4 Traffic conditions

Traffic conditions refer to dynamic, variable factors related to road traffic or obstacles that influence driving, including relationships with other vehicles, such as the distance to the vehicle ahead and the speed differential relative to it.

4.4.2.5 Vehicle status and dynamic information

Factors related to vehicle status and dynamic information pertain to the vehicle itself, as well as the relationship between the vehicle and the road. Vehicle status may be categorized into "vehicle condition" and "vehicle type".

4.4.3 Recording driving environment and conditions

The defined driving environments, conditions, appropriate driver behaviors, and/or cognitive demands associated with each evaluation item shall be recorded and documented. Specific examples are provided in Annex B.

4.5 Selecting evaluators

The examiner shall select at least five evaluators. The number of evaluators is specified in Clause 5.1 and Annex C.

Evaluators shall include practitioners with extensive experience in human factors and road safety, as well as individuals familiar with the functions of in-vehicle information interaction systems. Evaluators must possess a thorough understanding of traffic and road environments, and be capable of assessing and taking into account the safe presentation of information. Prior to conducting an evaluation, all evaluators shall have gained practical experience using the in-vehicle information interaction system.

It is recommended to record the basic profile of each evaluator. This shall include their area of expertise, knowledge of road safety, knowledge of human factors, and system knowledge regarding the generation of priority information (see Annex D).

4.6 Assessing the criticality and urgency of information

The examiner shall explain the contents of message and driving scenarios to the evaluator, ensuring that the evaluator's understanding of the scenarios and system functions aligns with the information conveyed by the examiner.

Examiners shall ensure that evaluators understand the evaluation dimensions (criticality and urgency) that constitute the priority index. Evaluators shall understand the four-tier ordinal rating scales used to assign ratings for criticality and urgency (see Tables 2 and

3). Each evaluator shall assume the role of a driver and assign a criticality and urgency rating to each piece of information.

NOTE 1.Generally speaking, urgency depends on time; controllability is one of the key factors considered when determining the urgency. If a situation is uncontrollable, the driver is not required

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