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COC damaged by a double number plate: is this the time to review your lighting?
- Updated:
- By: Kevin van Mierlo
The short answer
From 7 July 2026, semi-trailers, flatbeds and trailers in the O3 and O4 categories must have two positions for a rear number plate.
This means that existing type approvals will be reassessed.
In this article, you will read:
- Why does the double number plate mean you must update your COC?
- why now is the time to review your lighting package

Why the COC needs to be adapted
The European Commission has tightened the technical requirements for heavy trailers. This means that vehicles in categories O3 (3,500–10,000 kg) and O4 (>10,000 kg):
- Must have two separate spaces for mounting and fixing a rear registration plate
- offer the possibility of licence plate lights in both positions
The existing geometric requirements for mounting, height, visibility and lighting of the number plate remain fully in force, but now apply to both number plate positions. These are laid down in the UN ECE R48 regulation.
Adapting the COC can be seen as an opportunity
For many builders, this is an administrative and technical exercise that is normally rare. This is precisely why there is an opportunity to gain more than just processing the new registration plate obligation.
Why this is the right time to modernise your lighting system
The mandatory update primarily affects the rear of trailers in the O3 and O4 classes. There is usually already a significant amount of lighting in this area. We are seeing that vehicle builders are taking this opportunity to explore further improvements, such as greater standardisation or even redesigning the entire lighting system.

Especially in the context of staff shortages and a lack of experienced mechanics, this is an excellent opportunity to implement standardisation without incurring new costs for a separate change to the COC. This keeps your production process future-proof.
As a COC modification is costly, it may be an excellent time to implement improvements to the lighting system immediately.
Making workshop assembly time more efficient
Traditional methods require a lot of manual work, such as stripping, crimping, soldering, branching and testing. This is where most hours are spent.
The mandatory opening of the COC offers a logical moment to review this process and switch to modular plug-&-play systems. This can save significant time.
Better employability of less experienced mechanics
Workshops are increasingly facing a shortage of experienced staff. A plug-&-play approach makes the work more straightforward, reduces the risk of errors and ensures that new mechanics can work independently more quickly. A real boon for vehicle builders who fit a lot of lighting.
Lower warranty and repair costs
A small mistake during connection can quickly lead to interference.
Pre-tested, waterproof and pre-mounted connections significantly reduce these risks. Diagnosis and repair are also faster: unplugging and testing a connection or light is often enough to pinpoint the problem.
Prepared for upcoming technical requirements
In the coming years, stricter requirements are expected in the areas of EMC, CAN-bus integration and electric or connected trailers. By standardising now, you can avoid having to make further adjustments in a few years’ time.
For many vehicle builders, redesigning the lighting results in significant time savings
A lighting system redesigned with standardisation in mind saves time in both single piece and series production. This ensures a more stable and predictable assembly process.
Working cost-efficiently now that the COC has to be opened anyway
Breaking open the COC not only takes time, but also money. This is precisely why this is the time to make several adjustments at once. By including lighting and cabling solutions directly in the same modification, you avoid incurring new costs later.
Advice for your situation
Curious to find out what this could mean for your business? Take a look at the TRALERT® 24V lighting kits and discover how they are the perfect solution for smooth and time-saving mounting.
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Author
Kevin van Mierlo
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