An articulation system (1) for interconnecting first and second vehicle units of an articulated road vehicle comprises a central element (2) including a vertical cylinder with left and right arcuate walls (4) extending between two facing openings. First and second interconnecting structures (5) are joined to the central element (2) and are adapted to be respectively attached to the first and second vehicle units on opposed sides of the central element (2). Each interconnecting structure has a pitch joint member (5a) and a yaw joint member (5b). The pitch joint member (5a) has a frame (7) perpendicular to a longitudinal axis of a corresponding one of the first and second vehicle units and a pitch hinge mechanism (6) at a floor level to interconnect with the corresponding one of the first and second vehicle units. The yaw joint member (5b) has a frame (8) perpendicular to the longitudinal axis of the corresponding one of the first and second vehicle units and left and right arcuate walls juxtaposed to the left and right arcuate walls (4) of the vertical cylinder and rotatable therearound. The frame (7) of the pitch joint member (5a) and the frame (8) of the yaw joint member (5b) are juxtaposed and mechanically linked to jointly form a planar roll joint mechanism.