Guide To: UNECE R165 - Reverse Warning

UN ECE Regulation No. 165 provides the uniform provisions concerning the approval of audible reverse warning devices for motor vehicles. These devices are essential for improving the safety of vulnerable road users, such as pedestrians and cyclists, by emitting an audible warning when a vehicle is reversing. The regulation ensures that these devices meet specific performance and operational criteria to effectively alert those nearby.

Scope of the Regulation

UN ECE R165 applies to:

• Audible reverse warning devices intended for motor vehicles in categories M2, M3, N2, and N3 (buses, trucks, and heavy vehicles).

Key Features of UN ECE R165

1. Definitions and Classes of Devices:

   • An audible reverse warning device emits a sound when the vehicle is reversing to warn vulnerable road users.
   • Devices can be non-self-adjusting, self-adjusting, or stepwise self-adjusting, depending on their ability to adjust sound levels relative to ambient noise.
   • Devices are further categorized into classes (e.g., Class L, N, H) based on their sound output levels: Low, Normal, or High.

2. Sound Levels and Acoustic Characteristics:

   • Devices must emit sound between 62 dB(A) and 112 dB(A) depending on the class and the ambient noise. Self-adjusting devices ensure the sound is audible above the surrounding noise without being unnecessarily loud.
   • The regulation also defines broadband sounds and tonal sounds, ensuring that the emitted sound can be easily distinguished by nearby pedestrians and workers.

3. Environmental Durability:

   • Devices must be durable enough to withstand harsh environments, including exposure to dust, water, and varying temperatures. They must pass endurance tests to ensure functionality in different operational conditions.

4. Specifications for Installation and Operation:

   • The reverse warning devices must activate automatically when the vehicle is put into reverse gear and should be fitted in areas where they are most effective, typically the rear quarter of the vehicle.
   • Additionally, vehicles may be equipped with a pause function that temporarily disables the warning sound in certain conditions, such as when the vehicle is in a quiet area, but the function must reset each time the vehicle restarts.

5. Approval and Marking:

   • Devices that pass the tests must display an approval mark, which certifies that they meet the requirements of UN ECE R165. This approval is necessary for ensuring compliance with safety standards.

Conclusion

Audible reverse warning devices are crucial for preventing accidents involving pedestrians and other vulnerable road users when large vehicles are reversing. Compliance with UN ECE R165 ensures that these devices meet international standards for performance, durability, and safety. Manufacturers and fleet operators must ensure that vehicles are equipped with approved devices to enhance road safety and maintain regulatory compliance.