ISO 16121-2:2011

Road vehicles - Ergonomic requirements for the driver's workplace in line-service buses - Part 2: Visibility

ISO 16121-2:2011 specifies the requirements for the driver's field of view to the area in front of the vehicle, to the entrance opposite the driver's seat and the interior compartment. ISO 16121-2:2011 applies to the driver's workplace in low-floor line-service buses designed for the carriage of passengers, comprising more than eight seats in addition to the driver's seat, and having a maximum weight exceeding five metric tonnes and an overall width exceeding 2,30 m.

Véhicules routiers — Exigences ergonomiques du poste de conduite dans les bus de ville — Partie 2: Visibilité

General Information

• Status: Published
• Publication Date: 27-Jul-2011
• ICS: 13.180 - Ergonomics
• ICS: 43.080.20 - Buses
• Technical Committee: ISO/TC 22/SC 39 - Ergonomics
• Drafting Committee: ISO/TC 22/SC 39 - Ergonomics
• Current Stage: 9060 - Close of review
• Completion Date: 03-Jun-2028

Relations

• Revises: ISO 16121-2:2005 - Road vehicles - Ergonomic requirements for the driver's workplace in line-service buses - Part 2: Visibility
• Effective Date: 24-Apr-2010

Overview

ISO 16121-2:2011 - "Road vehicles - Ergonomic requirements for the driver's workplace in line-service buses - Part 2: Visibility" defines visibility requirements for drivers of low-floor line-service buses. The standard applies to buses designed to carry passengers (more than eight seats besides the driver), with a maximum weight > 5 tonnes and an overall width > 2.30 m. ISO 16121-2 focuses on the driver’s field of view to the road ahead, the entrance opposite the driver, and the interior passenger compartment to reduce blind spots and improve operational safety.

Key Topics and Requirements

• Vision points (V1 and V2): Defined as points 635 mm above the H-point with the seat in rearmost/highest (V1) and foremost/lowest (V2) positions within the required H-point adjustment range. These points are the basis for visibility checks.
• Forward blind spot: A bar equal to the vehicle width placed 300 mm in front of the foremost surface at 1 100 mm above ground must be visible (direct or indirect) from V1 and V2 for at least 95% of its length. If direct vision fails, alternative devices (e.g., mirrors or video systems) must be provided.
• Lateral visibility: Where a service door is at the front corner, a 100 × 100 × 100 mm cube positioned at 800 mm above ground must be visible (at least three-fourths of one face) from V1 and V2. Adjustable dashboards are checked in mid-position.
• View upwards: To ensure visibility of traffic signals, there must be an unobstructed view through the windscreen measured through a horizontal plane intersecting V1 with a 15° inclined plane.
• Passenger compartment observation: Mirrors or other devices shall allow monitoring of gangways and entrance/exit zones not in the driver’s direct line of sight.
• Reflections: Interior and exterior reflections that impede the driver's view or interfere with information devices must be minimized.

Applications and Who Uses It

ISO 16121-2 is used by:

• Bus and coach manufacturers (design and verification of driver’s cockpit and glazing)
• Automotive ergonomic engineers (human-centred cab layout)
• Transit authorities and fleet specifiers (procurement and safety requirements)
• Regulatory bodies and compliance auditors (type approval and conformity checks)
• Suppliers of mirrors, camera/video systems and visibility aids

Practical applications include design validation, visibility testing during prototype and production stages, selection of supplementary viewing systems, and improving driver situational awareness to reduce accidents and boarding incidents.

Related Standards

• ISO 16121-1: General description and basic requirements (normative reference)
• ISO 16121-3: Information devices and controls
• ISO 16121-4: Cabin environment

Note: Where national legislation exists, that legislation takes precedence for conflicting points.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 16121-2
Second edition
2011-08-01
Road vehicles — Ergonomic
requirements for the driver's workplace in
line-service buses —
Part 2:
Visibility
Véhicules routiers — Exigences ergonomiques du poste de conduite
dans les bus de ville —
Partie 2: Visibilité
Reference number
©
ISO 2011
©  ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2011 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Visibility.2
4.1 Forward blind spot .2
4.2 Lateral visibility .2
4.3 View upwards.2
4.4 View to passenger compartment .2
4.5 Reflections .3
Bibliography.6

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, Part 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 16121-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 13,
Ergonomics applicable to road vehicles.
This second edition cancels and replaces the first edition (ISO 16121-2:2005), which has been editorially
revised.
ISO 16121 consists of the following parts, under the general title Road vehicles — Ergonomic requirements
for the driver's workplace in line-service buses:
⎯ Part 1: General description, basic requirements
⎯ Part 2: Visibility
⎯ Part 3: Information devices and controls
⎯ Part 4: Cabin environment
iv © ISO 2011 – All rights reserved

Introduction
Poor ergonomics in the driver's workplace in buses designed to provide scheduled urban and interurban
services increase the already high physical and mental strains on the driver.
It is the aim of this part of ISO 16121 to supply the designer of line-service buses with information about how
to develop an overall ergonomic concept for the driver's workplace. The recommended requirements on the
driver's workplace for line-service buses made in this part of ISO 16121 are based on the scientific
conclusions of the research project “driver's workplace in the line-service bus”. This was conducted in
[1]
Germany and summarized in the VDV 234 recommendation. Further comprehensive ergonomic studies
related to the design of an enhanced driver workplace conducted in the United States, Canada, the
[2][3][4][5][6]
Netherlands, Sweden and the United Kingdom have been considered and found to provide
recommendations covering similar areas.
This part of ISO 16121 sets out to consider the practical implications for all ranges of drivers but particularly
those with statures from 1,55 m (small female) to 2,0 m (large male). These statures include shoes (∼30 mm).
It is also essential that the designer refers to the specifications and requirements of all parts of ISO 16121
(1 to 4) before completing the design of a driver's workplace.
It should be noted that where there is also national legislation covering any of the subjects contained herein,
then both should be complied with. However, if a contradiction between the two should arise in any specific
area, then the legislation shall prevail for that specific point only.

INTERNATIONAL STANDARD ISO 16121-2:2011(E)

Road vehicles — Ergonomic requirements for the driver's
workplace in line-service buses —
Part 2:
Visibility
1 Scope
This part of ISO 16121
...