Guide To: UNECE R4 - Registration Plate Lamps

Guide To: UNECE R4 - Registration Plate Lamps

UN ECE Regulation No. 4 establishes the uniform provisions concerning the approval of devices for the illumination of rear registration plates on power-driven vehicles and their trailers. This regulation ensures that these lighting devices provide sufficient illumination for vehicle registration plates, improving visibility and safety on the road.

Scope of the Regulation

UN ECE R4 applies to rear registration plate lamps for the following vehicle categories:

• M: Passenger vehicles
• N: Goods vehicles
• O: Trailers
• T: Tractors.

Key Features of UN ECE R4

1. Design and Construction:

   • Rear registration plate lamps are designed to illuminate the area occupied by the registration plate uniformly without emitting excessive light directly towards the rear, except in cases where the device is grouped with a rear lamp.
   • The light must be colourless to avoid any significant alteration to the appearance of the registration plate.

2. Photometric and Colorimetric Requirements:

   • The regulation specifies the luminance required for the device to ensure the plate is clearly visible. At each measurement point, the luminance must be no less than 2.5 cd/m².
   • The gradient between luminance values must not exceed a specified limit to ensure uniform light distribution across the plate.

3. Marking and Approval:

   • Devices must bear the manufacturer's trade name or mark, along with a space for the approval mark.
   • The approval number and the letter "L" must be clearly displayed on the device.
   • Lamps may receive approval based on their conformity to this regulation, ensuring their compliance with international standards.

4. Durability and Testing:

   • The devices undergo rigorous testing to verify their photometric performance and durability under normal operating conditions.
   • Devices are tested for conformance to specifications, including angles of incidence and uniformity of light on the registration plate.

Incorporation into UN ECE R148

UN ECE R4 has been incorporated into UN ECE Regulation No. 148, which consolidates various regulations concerning vehicle light-signalling devices. By incorporating the provisions of R4, R148 streamlines the approval process for rear registration plate lamps, ensuring that they meet the necessary safety and performance standards under a single, harmonized regulation.

Conclusion

Rear registration plate illumination devices are essential for vehicle identification and safety. Compliance with UN ECE R4 (now part of UN ECE R148) ensures that these devices meet stringent international standards, providing reliable illumination of vehicle registration plates in various conditions. This regulation simplifies the approval process, making it easier for manufacturers to comply with global safety standards.