Note: this article describes the regulations in force in Poland. Requirements in other countries may differ – check your local rules.
How to position lights and reflectors on a trailer – dimensions and mounting rules
The regulations specify not only which lights are mandatory on a trailer, but also exactly where to mount them. Below I have collected the positioning requirements on the basis of the Regulation of the Minister of Infrastructure of 31 December 2002 (Journal of Laws (Dz.U.) 2024, item 502, as amended) and its technical annex. Information on which lights are required depending on the dimensions and mass of the trailer can be found in the post Mandatory trailer lighting.
Text updated 29.10.2026 – dimensions according to the regulation as worded in Dz.U. 2024, item 502, as amended.
Rear lighting – mounting
Every trailer must have at the rear: a position lamp, stop lamp, direction indicator, fog lamp and registration plate lamp. These functions are most often integrated in a single rear combination lamp.
Positioning requirements for rear lamps:
- max 400 mm from the side outline of the vehicle
- distance between the left and right lamp: min 600 mm
- mounting height: 250–900 mm
How to choose the lamp itself – number of functions, voltage, left and right versions – is covered in the article LED rear lamps for trailers – how to choose and connect.
Rear triangular reflectors – mounting
Two red triangular reflectors are mandatory on every trailer. The positioning requirements are the same as for rear lamps:
- max 400 mm from the side outline
- distance between them: min 600 mm
- height: 250–900 mm
You will find our range of reflectors at zemot.com.pl: Reflectors.
Front reflectors and front position lamps – mounting
Two white front reflectors are mandatory on every trailer. Positioning requirements:
- max 400 mm from the side outline
- distance between them: min 600 mm
- height: 250–900 mm
For trailers 1.6 m wide or more, white front position lamps are also mandatory – mounted according to the same rules.
Side reflectors – mounting
Amber side reflectors are mandatory on every trailer. Requirements:
- at least one reflector on each side within the middle third of the vehicle length (measured including the drawbar)
- the foremost one: max 3 m from the front outline of the trailer
- the rearmost one: max 1 m from the rear outline
- distance between adjacent reflectors on the same side: max 3 m (4 m is permitted if the vehicle design makes this impossible)
- height: 250–900 mm
Side marker lamps – mounting
Mandatory for trailers whose length including the drawbar exceeds 6 m. The positioning requirements are the same as for side reflectors. You will find side lamps in the Amber LED marker lamps category.
Front and rear end-outline marker lamps – mounting
Mandatory for trailers wider than 2.1 m (two at the front showing white, two at the rear showing red). Requirements:
- as close as possible to the side outline, but max 400 mm from it
- min 200 mm from the front or rear position lamps
- mounted as high as possible, keeping symmetry
Why marker lamps show white at the front and red at the rear is explained in LED marker lamps – colours and regulations. The requirements for agricultural trailers are described separately: Lighting and marking of agricultural vehicles, machines and trailers.
Retro-reflective contour marking – mounting
Required for trailers with a GVW > 3.5 t and width > 2.1 m (rear contour marking) and for trailers with a GVW > 3.5 t and length > 6 m registered after 10.10.2009 (side contour marking). Mounting rules:
- lower edge: 250–1500 mm above the ground
- the marking should cover the length and width of the vehicle as fully as possible
- with discontinuous marking, the gap may not exceed 50% of the length of the shortest strip element
Rear marking plates – large trailers
If a trailer with drawbar or a semi-trailer is longer than 10 m or has a GVW above 10 t, yellow retro-reflective plates with a red fluorescent border are mandatory.
Type approval
All lamps and reflectors fitted to a trailer must be type-approved for the given type of lighting or marking. LED lamps additionally require electromagnetic compatibility approval to ECE R10. The approval markings (the letter E in a circle) should be visible on the lamp housing or lens.