ISO 12353-2:2003 道路車両—交通事故分析—パート2：衝撃重大度測定の使用に関するガイドライン | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 12353-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 12, Passive safety crash protection systems.

ISO 12353 consists of the following parts, under the general title Road vehicles — Traffic accident analysis:

• Part 1: Vocabulary
• Part 2: Guidelines for the use of impact severity measures

Introduction

Any considered approach to road safety requires some concept of impact severity, which is normally thought of as the physical violence of a vehicle crash.

A government or other regulatory body implementing traffic-calming measures looks for a reduction in the severity of impacts on the modified roads; similarly, in introducing vehicle crash test regulations, it needs to know how the impact severity of the test configuration compares with the severity of impacts occurring on public roads.

Vehicle manufacturers seeking to improve the crashworthiness of their products also require some definition of impact severity, since the design changes that work best to provide occupant protection at low speeds are not necessarily — or even usually — also the best at high speeds.

Researchers and other investigators of real accidents provide data and advice to governments, manufacturers and other interested parties, and are required to produce measures of impact severity based on the evidence available to them after a crash has occurred.

Impact severity focuses on the vehicle, not the vehicle occupant, and in this context it is conventional to distinguish the first from the second collision. Typically, in a crash that results in occupant injuries there is first a collision between the vehicle and some other object, such as another vehicle, tree, or post: this is referred to as the first collision. A very short time later, some part of the interior passenger compartment, usually including a restraint system, is loaded by the occupant: this is referred to as the second collision.

Although these two collisions are not the same, they are obviously closely related, as the first collision creates most of the relevant conditions for the second. Prominent among these conditions is the direction and rate of vehicle deceleration, and the magnitude and rate of passenger compartment deformation.

Impact severity pertains to the violence of the first collision, and therefore does not directly determine the injury outcome. This leaves it possible to speak of low severity impacts that result in high injury levels, and vice versa. Generally, however, for a particular impact configuration, greater impact severity is associated with more severe injuries. The final outcome of the crash depends on the characteristics of the injury-reducing measures used, the human kinematics and the tolerance of the human body itself.

Measures of impact severity tend to be vehicle speed, velocity, acceleration or crush parameters. Some are easier to assess than others, and some are more relevant than others in particular accident circumstances. For this reason, a variety of measures is widely used.

Even when the impact severity parameters taken under consideration are correlated to the injury outcome, they are not necessarily responsible for injuries in terms of a causal reason. Other factors can also contribute to injury causation.

A description of these parameters, the information required to calculate them, and the methods by which they are assessed are given in Annex A.

The model shown in Figure 1 is an attempt to subdivide the sequence between the initial dose (physical input) and the response, defined as injury consequences. The parameters above the upper horizontal line are part of the pre-crash phase and constitute factors such as how the vehicle and the occupant appear in normal traffic immediately before impact. The dose, defined as the input into the complete system that cannot be affected by the vehicle, is the closing velocity. The parameters listed between the two horizontal lines occur during the crash phase (as defined in ISO 12353-1).

A complex dose–response system such as a vehicle impact can be divided into several different subdose–response systems according to the question under study. The different subdose–response systems may be seen within or between the shaded areas in Figure 1. Some of the factors influencing the injury outcome are hidden in the dynamic sequence, such as dynamic deformations, occupant trajectory and contact speed, while others, such as contact areas, change of velocity and final deformations of the vehicle, can be reconstructed or measured. In some cases, the dose–response model used depends on what it is possible to observe, estimate or measure, meaning that substitutes for better measurements are often used.

Clause 4 of this document is related to response in terms of injury, and Clause 5 is related to the vehicle response (e.g. deformations or interior damage).

1 Scope

This part of ISO 12353 describes the suitability of various measures for the determination of impact severity in road vehicle accidents. It also summarizes the main characteristics of the methods used for determining impact severity.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 12353-1 and ISO 6813 and the following apply.

Bibliography