Are there any restrictions or regulations on the brightness of trailer lamps to avoid causing interference to other road users?

There are indeed restrictions or regulations on the brightness of trailer lamps to avoid causing interference to other road users. Here are some relevant regulations and restrictions:
The light source emission must not affect others: According to the relevant provisions of the Road Traffic Safety Law, vehicles cannot affect other road traffic participants when driving. This means that the brightness of trailer lamps cannot be too high to avoid dazzling or interfering with drivers of other vehicles or pedestrians.
Specific brightness standards: Although the specific brightness standards of trailer lamps are not directly given in the reference article, the relevant regulations of automobile headlights can be referred to. For example, the brightness standard of a newly registered three-wheeled vehicle with a one-lamp system is not less than 8000 candela, and the brightness standard of a two-lamp system is not less than 6000 candela. These standards can be used as a reference to indicate that the brightness of the vehicle lighting system is limited.
Color temperature requirements: The color temperature of the headlights cannot exceed 6000K. If this value is exceeded, it will not pass the annual inspection. This also applies to trailer lamps, because too high a color temperature may cause interference to other road users.
Restrictions on modified or upgraded vehicle lights: If you modify or upgrade vehicle lights, you must ensure that they will not affect other road users. For example, when modifying headlights, you should choose integrated headlights to ensure that the light source will not cause interference to others. Similar principles should be followed for the modification or upgrade of trailer lights.
In summary, there are indeed restrictions or regulations on the brightness of trailer lamps. These regulations are intended to ensure that the brightness of the vehicle lighting system will not cause interference to other road users, thereby ensuring road traffic safety.