Improved warning red triangle

The invention relates to a warning red triangle (1) for signalling a stop along a road comprising a support base (2, 3) and a triangle shaped structure, made up of three foldable sides, characterised in that said triangle shaped structure provides three outer sides (4), comprised of, or coated with, retro reflector material, and three inner sides (5), each one of said inner sides being substantially parallel to a relevant outer side (4), said inner sides (5) being comprised of, or coated with, fluorescent material, said inner sides (5) being coupled to the relevant outer side (4) by means (7) allowing its positioning in a triangle (1) folding condition, in a position substantially parallel with respect to the relevant outer side (4).