ISO 16254-2024 PDF

Full title and description

ISO 16254:2024 — Acoustics — Measurement of sound emitted by road vehicles of category M and N at standstill and low speed operation — Engineering method. This International Standard specifies an engineering method for objective measurement of sound emitted by motor vehicles (categories M and N) under stationary and low-speed operating conditions, and includes provisions for assessing external sound generation systems and a psychoacoustic tonality metric to aid audibility evaluation for pedestrian safety.

Abstract

This document is derived from ISO 362‑1 and defines an engineering test method that reproduces the sound level and spectral characteristics of principal vehicle sound sources in stationary and low-speed conditions. The method is intended to be simple yet reproducible, requires an extensive open acoustic environment, and provides objective metrics (sound pressure level, frequency content, level changes with speed and a psychoacoustic tonality metric) suitable for type approval, manufacturing checks and official testing.

General information

• Status: Published.
• Publication date: December 2024 (Edition 2, published 11 Dec 2024 in vendor listings).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.140.30 (Noise emitted by means of transport).
• Edition / version: Edition 2 (2024).
• Number of pages: 54 (ISO publication).

Scope

Specifies an engineering measurement method for the external sound of road vehicles of categories M and N at standstill and during low-speed operation. The scope includes measurement environment requirements (an extensive open space), procedures to characterise sound pressure level and frequency content, and objective criteria to report the behaviour of external sound generation systems intended to inform pedestrians. The standard adds a psychoacoustic tonality metric to help identify audible tonal components.

Key topics and requirements

• Engineering method derived from ISO 362‑1 for stationary and low-speed vehicle conditions.
• Measurement environment: extensive open space with specified acoustic conditions to ensure reproducibility.
• Objective metrics: sound pressure level, frequency content, level/spectral changes with speed and psychoacoustic tonality.
• Procedures to evaluate external sound generation systems (ESGS) used to provide pedestrian warning/awareness.
• Designed for use in type approval, manufacturing quality checks and official testing stations.

Typical use and users

Used by regulatory authorities, type-approval bodies, vehicle manufacturers (NVH and acoustics teams), accredited test laboratories, validation & verification engineers for external sound generation systems, and researchers studying vehicle acoustics or pedestrian safety. Typical applications include type approval testing, pre-delivery inspection, production spot checks and R&D validation of EV/HEV acoustic systems.

Related standards

Closely related to ISO 362‑1 (engineering method for measuring noise from accelerating road vehicles — Part 1: M and N categories), from which this document is derived; also connected to other ISO vehicle-acoustics parts (for accelerating tests, indoor/semi-anechoic chamber methods, and specific vehicle classes). The 2016 edition (ISO 16254:2016) was withdrawn and superseded by this 2024 edition.

Keywords

Acoustics; vehicle exterior noise; sound emission; road vehicles; category M; category N; engineering method; type approval; external sound generation system; psychoacoustic tonality; pedestrian safety; NVH testing.

FAQ

Q: What is this standard?

A: ISO 16254:2024 is an International Standard that specifies an engineering method to measure sound emitted by road vehicles of categories M and N at standstill and low speed operation.

Q: What does it cover?

A: It covers test environment requirements, measurement procedures, objective metrics (level, spectral content, tonal audibility) and assessment of external sound generation systems used to provide acoustic information to pedestrians. The method is intended for reproducible, objective results under specified open-area acoustic conditions.

Q: Who typically uses it?

A: Regulatory bodies, type-approval and certification labs, vehicle manufacturers (NVH engineers), test houses and researchers working on vehicle exterior noise and pedestrian-audibility issues.

Q: Is it current or superseded?

A: Current — ISO 16254:2024 (Edition 2, published in December 2024) is the published, active edition and supersedes ISO 16254:2016 (withdrawn).

Q: Is it part of a series?

A: Yes — it is part of the ISO vehicle-acoustics family and is explicitly derived from and aligned with ISO 362‑1 (measurement methods for accelerating/urban driving conditions). Other related parts (e.g., indoor testing, other vehicle classes) form the broader set of ISO vehicle noise standards.

Q: What are the key keywords?

A: Acoustics, vehicle exterior noise, engineering method, category M, category N, external sound generation, tonality, type approval.