this invention relates to a pre - cast concrete traffic barrier element and a method of constructing a traffic barrier using the element on a vertical face of a retaining wall . the barrier element is a profiled reinforced block of concrete having a bottom surface with a longitudinally extending channel therein . the traffic barrier element is supported on the retaining wall with a top surface of the retaining wall being received within the channel . u - shaped anchoring bars project from an interior portion of the traffic barrier element and from the top surface of the retaining wall to form an oval keyway the length of the longitudinal channel . a locking bar arrangement is inserted through the keyway in a locking relationship with the u - shaped anchoring bars . sealing material between the traffic barrier element and the retaining wall and between the traffic barrier element and the ground adjacent to the retaining wall on the traffic side prevents the leakage of grout and leveling of the barrier element . grout is then injected throughout the longitudinal channel and allowed to harden , thus providing a sealed and locked joint .