Europe
Europe
UN R165 Audible reverse warning devices
"Audible reverse warning device" means a device, emitting an acoustic signal to the outside of a vehicle while reversing, which is intended to give audible warning of the presence of a vehicle. A reverse warning sound is widely used to ensure safety of people around medium- and heavy-duty vehicles above 3.5 tonnes. However, until 21 June 2022, there has been no worldwide harmonized regulation for audible reverse warning. To reduce the risk of accidents with reversing vehicles, on the one hand, and complaints about their noisiness, on the other, a regulation for reverse warning sound has become necessary.
On 13 March 2023, the World Forum for Harmonisation of Vehicle Regulations (WP.29) adopted a new UN regulation on reversing warnings, UN R165. The regulation was drafted by a group of experts from government and industry, led by Japan, and came into force on the day of its adoption. The new regulation strikes a balance between ensuring a sufficiently recognisable warning sound and avoiding undue noise nuisance to the environment and humans, including provisions for conventional reversing warning devices with a fixed volume and adjustable devices that automatically select the appropriate volume according to ambient noise.
ATIC experts are working under designated technical services in Europe to conduct Initial Assessment, Witness Testing and CoP assessment as authorized inspectors under authorities including e/E4 Netherland, e/E5 Sweden, e/E13 Luxembourg, e/E24 Ireland, e/E49 Cyprus.
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General Steps
General Steps
Application
Manufacturer submits application documents
Manufacturer submits system functionality and system validation documents
Initial Assessment
ATIC experts review application document.
ATIC experts evaluate the documentation package.
Testing
ATIC experts assess the manufacturer's test plan and capability, then perform the test based on the proposed protocol
Approval
Authority will review and issue type approval certificate if all the documents, tests, drawings fulfill the regulation and requirements.
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R165 Definitions
R165 Definitions
1. "Audible reverse warning device" means a device, emitting an acoustic signal to the outside of a vehicle while reversing, which is intended to give audible warning of the presence of a vehicle, with the primary purpose to fulfil the requirements of this Regulation;
2. "Non-self-adjusting audible reverse warning device" means a device which gives audible reverse warning sound independent of "Ambient noise" levels.
3. "Self-adjusting audible reverse warning device" means a device which automatically adjusts its sound level, throughout a defined range, in order to maintain a sound level differential between the sound output of the device and the "Ambient noise" measured by itself.
4. "Stepwise self-adjusting audible reverse warning device" means a device which automatically adjusts to a fixed sound level (covering Low level, Normal level or High level), depending on the "Ambient noise" measured by itself.
5. "Multiple audible reverse warning system" means a combination of "Non-self-adjusting audible reverse warning devices" capable of functioning independently when applying "Low level", "Normal level", "High level";
6. Background and ambient noise：
- "Background noise" is any disturbing sound other than the sound signal of the audible reverse warning device at test conditions in this regulation. Its sound pressure level is measured in dB(A) and the area considered around the vehicle is regarded as a homogeneous sound field with the same sound pressure level.
- "Ambient noise" is any disturbing sound other than the sound signal of the audible reverse warning device, around the audible reverse warning device and the vehicle. Its sound pressure level is measured in dB(A) and the area considered around the vehicle is regarded as a homogeneous sound field with the same sound pressure level.
7. "Pause function" means a mechanism to halt temporarily the operation of a reverse warning device.
Part I :
Approval of audible reverse warning devices；
Part II :
Approval of the motor vehicles of categories M2 (M > 3500 kg), N2, N3 and M3.
Basic principle
Basic principle
The audible reverse warning device that sends sound signals to the outside of the car when reversing, and its function is to send sound warnings to the surrounding vehicles. It is divided into four types according to the way it responds to environmental noise, namely, non-self-adjusting audible reverse warning device self-adjusting audible reverse warning device, stepped self-adjusting audible reverse warning device and multiple audible reverse warning system.The audible reverse warning device shall have acoustic characteristics and mechanical characteristics at the meanwhile.
The acoustic characteristics of the warning sound emitted by the audible reverse warning device are mainly the A-weighted sound pressure level, the sound transmission interval and the sound frequency. The A-weighted sound pressure level is a direct reflection of the ambient noise level (in dB) and affects the level of the warning sound emitted by the reversing warning device.
When the audible reverse warning device is activated, the endurance may vary due to ambient temperature, operating time, vibration, dust, water, etc. As the most important mechanical characteristic of a reversing audible warning device, endurance needs to be adequately and extensively tested.
Part I : Audible reverse warning device
Part I : Audible reverse warning device
1. Requirements for the audible signal to be emitted by the audible reverse warning device
- The pattern of the audible signal, including at least one silent part, shall be repeatable from 24 to 120 times per minute;
- This requirement applies only to non-self-adjusting audible reverse warning device if they are powered by alternating current;
- Two samples are required to be provided for all tests.
2. Alternative sounds
May be selected by the driver, provided they comply with the provisions in the test methods below and are approved.
1. Test instruments
4. Mechanical characteristics test
- Acoustic measurements:
A sound level meter or equivalent measurement system.
- Mechanical characteristics test:
Instrument for testing voltage, resistance, distance, time and ambient conditions including temperature, wind speed, air pressure and relative humidity.
2. Test site
|  |
3. Measurement of the sound characteristics of the "Audible reverse warning device
* The multiple audible reverse warning system is the same as this one. 
 Sound level requirements to be met by the test results:  Remark 1: In practical design, the deviation between the measured values of low and normal levels is not less than 5 dB(A). Remark2：The sound level ranges of the "Self-adjusting audible reverse warning device" and the "Stepwise self-adjusting reverse warning device" at different levels correspond to the reference levels of environmental noise. Reference levels for ambient noise (divided into three levels): Reference level 1 :45 dB(A) ± 2 dB(A) Reference level 2 :60 dB(A) ± 2 dB(A) Reference level 3 :80 dB(A) ± 2 dB(A) | |
Endurance test：
Temperature durability testing in series;
Durability continuous test;
Vibration endurance test.
No. | Test items | Remarks |
1 | Acoustic test |
|
| 2 | Endurance test |
|
Part II :Audible reverse warning signals for motor vehicles
Part II :Audible reverse warning signals for motor vehicles
1. General
- Capable of emitting sound and self-starting (when reverse gear is selected and propulsion system is on);
- Resistant to vibration (design, construction, assembly);
- Resistant to corrosion (including regional climate differences, design, construction, assembly);
- In case a device has more than one mode, the reverse warning device shall be automatically activated to its default mode when the vehicle is restarted following each vehicle turn-off. For "Non-self-adjusting audible reverse warning device", "Multiple audible reverse warning system", and for "Stepwise self-adjusting audible reverse warning device" the default mode is the "Normal level".
- Alternative sounds: may be selected by the driver, provided they comply with the provisions in the test methods below and are approved.
- At the time of application of this Regulation, Contracting Parties shall declare which Classes of the "Non-self-adjusting audible reverse warning device" (N, I, II, III) and / or the "Multiple audible reverse warning system" (M-I, M-II, M-III) of this Regulation they intend to mandate in their territory for each category of vehicles if the vehicles in questions are not equipped with either a "Self-adjusting audible reverse warning device" or a "Stepwise self-adjusting audible reverse warning device".
* Devices of class L or H shall only be used in combination with devices of other classes which includes “Normal level”.
2. Specifications regarding sound levels
Requirements for measured values：
See the corresponding test report and communication file for the model shown in Annex 1B for the required values.
3. Pause function
The manufacturer may install a pause function to disable temporarily the audible reverse warning device when a vehicle of category M2 (M>3500 kg), N2, M3 or N3 is equipped with a non-audible safety system, device(s) for means of rear visibility or detection as described in UN Regulation No. 158, paragraph 1.3, allowing the driver to check the hazard area behind the vehicle, including when towing vehicle(s) of category O, and it is ensured that such safety system(s) functions while reversing. Any other disabling function which does not satisfy the specifications below is prohibited.
1. Specification of sound pressure levels and instrumentation
Use instruments that meet the specifications specified in Part I.
| 2. Test site Use a silenced or semi-silenced site that complies with the specifications in Part I. | |
3. Specification of the test vehicle
| |
4. Measurement on stationary vehicle of the sound characteristics of the audible reverse warning device （background noise）
the arrangement of the installation is shown below on the left and measure the A-weighted sound pressure level of the sound emitted by the reversing warning device via a microphone according to the flow chart on the right below. 
the arrangement of the installation is shown below on the left and measure the A-weighted sound pressure level of the sound emitted by the reversing warning device and loudspeaker via a microphone according to the flow chart on the right below.  | |
Sound level requirements to be met by the test results:
Non-self-adjusting audible reverse warning device | Stepwise self-adjusting reverse warning device | Self-adjusting audible reverse warning device | |
Low level | =45 dB(A）and ＜60 dB(A) | 在45dB(A）至95dB(A）范围内 | |
Normal level | =60 dB(A）and ≤75 dB(A) | ||
High level | =80 dB(A）and ≤95 dB(A) | ||
Remark: In practical design, the deviation between the measured values of low and normal levels is not less than 5 dB(A).
When the test results are unsatisfactory, perhaps due to the large interference of background noise, some correction of the background noise is required. The correction method is as shown in the figure below. When correcting, the background noise is sampled for 10 seconds, and the highest A-weighted sound pressure level is used as the background noise, and the correction is made according to the following requirements: (see the table on the next page)
Correction for "Background noise | ||
Range of maximum to minimum value of the representative "Background noise" A-weighted sound pressure level over a defined time period. ∆Lbgn, p-p in dB(A) | Sound pressure level of test result minus "Background noise" level ∆L = Ltest - Lbgn in dB(A) | Lcorr Correction in dB(A) |
- | ΔL≥10 | No correction needed |
≤4 | 8≤ΔL<10 | 0,5 |
6≤ΔL<8 | 1,0 | |
4.5≤ΔL<6 | 1,5 | |
3≤ΔL<4.5 | 2,5 | |
ΔL <3 | No valid measurementcan be reported | |
No. | Test items | Remarks |
| 1 | Stationary vehicles acoustic test | |
| 2 | The pause function test | Field of view: with rear visibility or detection device in accordance with UN R158, paragraph 1.3 |
R165 Certificate of approval
R165 Certificate of approval
Components:
Components can be certified (see paragraphs 3 to 5 in Part I of the regulations for details).
Whole vehicle:
- If the audible reverse warning device installed on the vehicle has obtained a certificate of approval for the component, only the whole vehicle needs to be certified;
- Otherwise, in addition to the need to obtain a certificate of conformity for the whole vehicle, it is also necessary to do the corresponding endurance test for the parts of the whole vehicle, but it is not necessary to do the certification of the parts.
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