Modular separator for cycle paths or other road application, made by a lower element called "Base" and an upper element called "Extension" wherein: • the Base and the Extension are vertically mounted one on the other and horizontally offset so that the upper Extension may rest symmetrically on two lower Bases, • the Base consists in a trapezoidal section shape made by two upper side rails placed at the edge of the Base profile (21,22) forming a central channel within them able to determine a surface for the interlocking of the Extension element, • the Base is equipped with a concave side wall made by variable radius of curvature with geometric progression on the side designed to contain the cycle path, and an opposite side wall with an orthogonal profile with respect to the plane of the roadway combined in the upper part to a profile with constant concave curvature, • the lateral side walls (85,86) are equipped with a disconnect system from the remaining body of the Base (81,82) by an interlocking coupling and/or screw (83,84), • the surface of side walls of the Base have a series of protuberances with a rounded shape arranged along the horizontal development of the modular separator (101,102), • the profiles of the front wall of the Base and the back wall have a reciprocal and curved shape, • the Extension consists of a parallelepiped shape made up of a profile with a central block in the lower part complementary to the shape of the Base channel with a central channeling and equipped in the upper area with a linear or convex profile, • the Base and Extension elements joined together have vertical through holes for fixing screws (63,65) that align each other only when an upper Extension rests symmetrically on two lower Bases (61,62). • the Base and the Extension are vertically mounted one on the other and horizontally offset so that the upper Extension may rest symmetrically on two lower Bases, • the Base consists in a trapezoidal section shape made by two upper side rails placed at the edge of the Base profile (21,22) forming a central channel within them able to determine a surface for the interlocking of the Extension element, • the Base is equipped with a concave side wall made by variable radius of curvature with geometric progression on the side designed to contain the cycle path, and an opposite side wall with an orthogonal profile with respect to the plane of the roadway combined in the upper part to a profile with constant concave curvature, • the lateral side walls (85,86) are equipped with a disconnect system from the remaining body of the Base (81,82) by an interlocking coupling and/or screw (83,84), • the surface of side walls of the Base have a series of protuberances with a rounded shape arranged along the horizontal development of the modular separator (101,102), • the profiles of the front wall of the Base and the back wall have a reciprocal and curved shape, • the Extension consists of a parallelepiped shape made up of a profile with a central block in the lower part complementary to the shape of the Base channel with a central channeling and equipped in the upper area with a linear or convex profile, • the Base and Extension elements joined together have vertical through holes for fixing screws (63,65) that align each other only when an upper Extension rests symmetrically on two lower Bases (61,62).