Road barrier (100), comprising a box-like structure extending along a first direction of greater extension; having a tapered upper portion (101, 102; 103) and a lower portion (104), joined to said upper portion; an enlarged base extending, along a second direction orthogonal with respect to said first direction of greater extension, by a width greater than the width that said tapered upper portion has along said same second direction; said barrier (100) being adapted in use for being at least temporarily rigidly anchored to the ground or road surface in correspondence of the lower portion (104) thereof; said barrier comprising at least one first wheeled trolley (210), axially mobile along a third direction orthogonal with respect to said first and second direction.