ISO 9815:2024
(Main)Road vehicles — Passenger-car and trailer combinations — Lateral stability test
Road vehicles — Passenger-car and trailer combinations — Lateral stability test
This document specifies a lateral stability test for passenger-car and trailer combinations. It is applicable to passenger cars in accordance with ISO 3833, and also to light trucks and their trailer combinations. The lateral stability test determines the damping characteristic of the yaw oscillation of such towing-vehicle–trailer combinations excited by a defined steering impulse. The combination is initially driven in a steady-state, straight-ahead driving condition. Oscillation of the vehicle is then initiated by the application of a single impulse of steering, followed by a period in which steering is held fixed and the oscillation of the combination is allowed to damp out. Testing is conducted at several constant speeds. Where non-periodic instability is of interest, a steady-state circular test is specified.
Véhicules routiers — Ensembles voiture particulière et remorque — Essai de stabilité latérale
General Information
Relations
Standards Content (Sample)
International
Standard
ISO 9815
Fourth edition
Road vehicles — Passenger-car
2024-09
and trailer combinations — Lateral
stability test
Véhicules routiers — Ensembles voiture particulière et remorque
— Essai de stabilité latérale
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions . 1
4 Measurement variables . 2
5 General conditions . 2
5.1 Conformity .2
5.2 Measuring equipment .2
5.3 Test track .2
5.4 Wind velocity .3
5.5 Loading conditions.3
5.5.1 Towing vehicle .3
5.5.2 Trailer .3
5.5.3 Static load on the coupling ball .3
5.5.4 Adjustment of load-distributing coupling mechanisms .4
6 Test method . 5
6.1 General .5
6.2 Test runs .5
6.2.1 Speed .5
6.2.2 Steering impulse .5
6.2.3 Number of test runs .7
7 Data analysis . 7
7.1 General .7
7.2 Individual test runs .8
7.2.1 Effective longitudinal vehicle acceleration .8
7.2.2 Test speed .8
7.2.3 Damping the oscillation of the articulation angle .8
7.2.4 Yaw velocity ratio .9
7.3 Zero-damping speed . .10
7.4 Reference-damping speed .10
7.5 Reference-speed damping .10
8 Data presentation . 10
8.1 General data .10
8.2 Test conditions .10
8.3 Results . .11
Annex A (normative) Test report — General data (supplement to ISO 15037-1:2019, Annex A) .12
Annex B (normative) Test results .15
Annex C (informative) Steady-state behaviour .16
Bibliography . 17
iii
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
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 33, Vehicle
dynamics, chassis components and driving automation systems testing.
This fourth edition cancels and replaces the third edition (ISO 9815:2010), which has been technically
revised.
The main changes are as follows:
— additions have been made to 6.2.1, 6.2.2 and 6.2.3;
— additions have been made to 7.2.1, 7.2.2, 7.2.3 and 7.2.4;
— references have been updated to ISO 4138:2021 and ISO 15037-1:2019.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The main purpose of this document is to provide repeatable and discriminatory test results.
The dynamic behaviour of a road vehicle is a very important aspect of active vehicle safety. Any given vehicle,
together with its driver and the prevailing environment, constitutes a closed-loop system that is unique. The
task of evaluating the dynamic behaviour is therefore very difficult since the significant interaction of these
driver-vehicle-environment elements are each complex in themselves. A complete and accurate description
of the behaviour of the road vehicle must necessarily involve information obtained from a number of
different tests.
Since this test method quantifies only one small part of the complete vehicle handling characteristics, the
results of these tests can only be considered significant for a correspondingly small part of the overall
dynamic behaviour.
Moreover, insufficient knowledge is available concerning the relationship between overall vehicle dynamic
properties and accident avoidance. A substantial amount of work is necessary to acquire sufficient and
reliable data on the correlation between accident avoidance and vehicle dynamic properties in general
and the results of these tests in particular. Consequently, any application of this test method for regulation
purposes requires proven correlation between test results and accident statistics.
v
International Standard ISO 9815:2024(en)
Road vehicles — Passenger-car and trailer combinations —
Lateral stability test
1 Scope
This document specifies a lateral stability test for passenger-car and trailer combinations. It is applicable to
passenger cars in accordance with ISO 3833, and also to light trucks and their trailer combinations.
The lateral stability test determines the damping characteristic of the yaw oscillation of such towing-
vehicle–trailer combinations excited by a defined steering impulse. The combination is initially driven in a
steady-state, straight-ahead driving condition. Oscillation of the vehicle is then initiated by the application
of a single impulse of steering, followed by a period in wh
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