ISO 19377:2017

Heavy commercial vehicles and buses - Emergency braking on a defined path - Test method for trajectory measurement

ISO 19377:2017 describes test methods for determining the deviation of the path travelled by a vehicle during a braking manoeuvre induced by an emergency braking system from a pre-defined desired path. The purpose of this document is the evaluation of the vehicle path during and following the system intervention. The corrective steering actions for keeping the vehicle on the desired path can be applied either by the driver or by a steering machine or by a driver assistance system. By making this document open for either open-loop or closed-loop testing, it is possible to apply the test method for evaluating how well the vehicle can be kept within user-defined lane markings after the system intervention, and also for evaluating the precision of the interaction between the emergency braking system and an active lane keeping system. This document applies to heavy vehicles equipped with an advanced emergency braking system (AEBS), including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). NOTE The test method is intended to evaluate the entire vehicle behaviour, not for defining system requirements for the AEBS, which is done in the respective standards created by ISO/TC 204.

Véhicules utilitaires lourds et autobus — Freinage d’urgence sur un passage défini — Méthodes d’essai pour la mesure de trajectoire

General Information

• Status: Published
• Publication Date: 03-Dec-2017
• ICS: 43.080.01 - Commercial vehicles in general
• Technical Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Drafting Committee: ISO/TC 22/SC 33/WG 6 - Vehicle dynamics of heavy commercial vehicles and buses
• Current Stage: 9092 - International Standard to be revised
• Start Date: 26-Feb-2024
• Completion Date: 13-Dec-2025

Overview - ISO 19377:2017 (Emergency braking trajectory measurement)

ISO 19377:2017 specifies a repeatable test method to measure the deviation of the actual vehicle path from a pre-defined desired path when an Advanced Emergency Braking System (AEBS) intervenes. It applies to heavy commercial vehicles and buses (vehicle classes per ISO 3833: trucks and trailers >3.5 t; buses/articulated buses >5 t - categories M3, N2, N3, O3, O4). The standard evaluates the vehicle trajectory during and after AEBS activation (open-loop or closed-loop) and is intended to quantify whole-vehicle behaviour rather than set AEBS performance requirements.

Key topics and technical requirements

• Test principle: Trigger AEBS (external input) during straight-line or constant-radius curve driving; AEBS must remain active until vehicle standstill. Tests can be open-loop (fixed steering) or closed-loop (driver, steering robot or lane-keeping system may correct steering).
• Measured variables: longitudinal velocity, steering-wheel angle, activation time, longitudinal/lateral positions of the vehicle reference point and axles, longitudinal/lateral accelerations, yaw and articulation angles (recommended).
• Trajectory metrics: maximum path deviation (vehicle, rear axle, trailer), deceleration at full braking, maximum articulation angle(s), corrective steering action (for closed-loop), indication of leaving the desired track.
• Measuring equipment: recommended use of position measurement systems (e.g., differential GPS) and photoelectric barriers for repeatable trigger location. Recommended maximum combined position error: ±0.05 m; yaw angle error: ±1°.
• Test conditions: even road surface with uniform friction per ISO 15037-2; vehicle condition and loading must be recorded; test track and ambient conditions documented.
• Data evaluation: standard defines how to compute and present characteristic values and test reports (annexes provide templates and examples).

Applications - practical value

• Validate how well heavy vehicles and bus platforms remain within a lane or desired path after AEBS intervention.
• Assess interactions between AEBS and lane-keeping systems or steering robots.
• Support vehicle dynamics development, system integration, and safety verification by quantifying trajectory control during emergency braking.
• Provide repeatable laboratory and field test procedures for OEMs, Tier‑1 suppliers, independent test labs and research institutes evaluating AEBS and active steering systems.

Who should use it

• Vehicle manufacturers and system integrators (AEBS, ADAS, lane-keeping)
• Test laboratories and certification bodies
• Automotive safety engineers and vehicle dynamics researchers
• Regulators and standards developers comparing test outcomes or harmonizing procedures

Related standards

• ISO 15037-2: General conditions for heavy vehicle dynamics tests
• ISO 16552: Stopping distance tests for heavy vehicles with ABS
• ISO 8855: Vehicle dynamics vocabulary
• ISO 3833: Vehicle classification (heavy vehicles and buses)
• AEBS system standards developed by ISO/TC 204 (for system requirements)

Keywords: ISO 19377:2017, emergency braking, AEBS, heavy commercial vehicles, buses, trajectory measurement, test method, vehicle path deviation, differential GPS, steering robot.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19377
First edition
2017-11
Heavy commercial vehicles and
buses — Emergency braking on a
defined path — Test method for
trajectory measurement
Véhicules utilitaires lourds et autobus — Freinage d’urgence sur un
passage défini — Méthodes d’essai pour la mesure de trajectoire
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Variables . 2
6 Measuring equipment . 3
7 Test conditions . 3
7.1 General . 3
7.2 Test track and ambient conditions . 4
7.3 Test vehicle . 4
7.3.1 General vehicle condition . 4
7.3.2 Loading condition . 4
7.3.3 Number of test runs . 4
8 Test methods . 4
8.1 Test method for braking straight ahead . 4
8.1.1 Initial driving condition . 4
8.1.2 Definition of the desired path and track. 4
8.1.3 System intervention . 5
8.2 Test method for braking in a constant radius curve . 5
8.2.1 Initial driving condition . 5
8.2.2 Definition of the desired path and track. 5
8.2.3 System intervention . 6
9 Data evaluation and presentation of results . 6
9.1 General . 6
9.2 Characteristic values . 7
9.2.1 Maximum path deviation, D .
P,max 7
9.2.2 Maximum rear axle path deviation, D .
PR,max 7
9.2.3 Maximum trailer path deviation, D .
PT,max 8
9.2.4 Deceleration at full braking . 8
9.2.5 Maximum articulation angle(s) (optional) . 8
9.2.6 Corrective steering action, δ (for closed-loop test) . 8
H,C
9.2.7 Indication of leaving the desired track (optional) . 8
Annex A (normative) Test report — General data and test conditions. 9
Annex B (informative) Example of test reports .10
Bibliography .12
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
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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URL: www.iso.org/iso/foreword.html.
This document was prepared by ISO/TC 22, Road vehicles, Subcommittee SC 33, Vehicle dynamics and
chassis components.
iv © ISO 2017 – All rights reserved

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 requires 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 will require proven correlation between test results and accident
statistics.
INTERNATIONAL STANDARD ISO 19377:2017(E)
Heavy commercial vehicles and buses — Emergency
braking on a defined path — Test method for trajectory
measurement
1 Scope
This document describes test methods for determining the deviation of the path travelled by a vehicle
during a braking manoeuvre induced by an emergency braking system from a pre-defined desired path.
The purpose of this document is the evaluation of the vehicle path during and following the system
intervention. The corrective steering actions for keeping the vehicle on the desired path can be applied
either by the driver or by a steering machine or by a driver assistance system. By making this document
open for either open-loop or closed-loop testing, it is possible to apply the test method for evaluating
how well the vehicle can be kept within user-defined lane markings after the system intervention,
and also for evaluating the precision of the interaction between the emergency braking system and an
active lane keeping system.
This document applies to heavy vehicles equipped with an advanced emergency braking system
(AEBS), including commercial vehicles, commercial vehicle combinations, buses and articulated buses
as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and
articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification,
categories M3, N , N3, O3 and O4).
NOTE The test method is intended to evaluate the entire vehicle behaviour, not for defining system
requirements for the AEBS, which is done in the respective standards created by ISO/TC 204.
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 edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8855:2011, Road vehicles — Vehicle dynamics and road-holding ability — Vocabulary
ISO 15037-2:2002, Road vehicles — Vehicle dynamics test methods — Part 2: General conditions for heavy
vehicles and buses
ISO 16552:2015, Heavy commercial vehicles and buses — Stopping distance at straight-line braking with
ABS — Open-loop and closed-loop test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8855 and ISO 15037-2 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
vehicle reference point
point fixed in the vehicle
Note 1 to entry: For use with this document, the vehicle reference point of the first vehicle unit shall be set to the
following:
— X = 0 at the wheel centre of the first axle;
V
— Y = 0 at the centre of the connection line between the tyre contact centres of the first axle;
V
— Z = 0 on ground level.
V
3.2
activation time
t
point in time of intervention of the AEBS, given by a trigger signal
3.3
vehicle reference position
X , Y
0 0
lateral and longitudinal position of the reference point of the first vehicle unit at the activation time (3.2)
3.4
path deviation
D
Pn
shortest distance between the desired vehicle path and the position of the reference point of vehicle
unit, n, at a certain point in time, t
4 Principle
This document specifies a method to determine the deviation of the vehicle from a defined path. The
driving situation represents an intervention of an advanced emergency braking system during straight-
ahead driving or in a curve on an even road surface with a uniform coefficient of friction as specified in
ISO 15037-2. It is necessary that the emergency braking system of the test vehicle allows an external input
for triggering the system intervention. After the triggering, the AEBS shall remain active until vehicle
standstill. The test may be conducted as open-loop or as a closed-loop test. In case of an open-loop test,
the steering wheel angle is kept to its initial value. In case of a closed-loop test, the driver (or a steering
robot) or a lane keeping assistance system or both attempt to keep the vehicle on the desired path.
If the test is conducted with corrective steering actions by the driver, the results will strongly depend on
the driver activities. This should be considered when comparing closed-loop test results. For excluding
the driver influence during a closed-loop test, it is recommended to conduct the test with a steering
robot which has the capability to be programmed for a desired path via GPS feedback.
NOTE By leaving the test method open for interventions of driver assistance systems other than the
emergency braking system, the interact
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