Disclosed herein are embodiments of a roadside barrier segment to sit on top of a retaining wall to provide impact resistance to vehicular traffic. Concrete traffic barriers are pre-cast in a controlled manufacturing environment then transported as a modular precast concrete segment to the jobsite and installed interlocking directly on top of an earth retaining wall. The precast concrete segment is designed to have a counterweight from soil backfill on a stem of the precast segment that resists overturning pressures from vehicle impact on the traffic barrier segment that extends above the roadway surface. The stem may be triangular in shape to capture more of the backfill soil. A vertical node may be placed on one side of the segment and a receiving channel on the opposite side of the segment to allow the interaction of adjacent segments to share impact loads from motor vehicles.