Precast traffic barriers, or copings, are a solution for retaining walls with vehicular or pedestrian traffic on top. In 2018  86km of coping were supplied. It allows a contractor to set precast barrier units along the top of the wall, greatly reducing the use of cast-in-place concrete. The barrier units are designed to rest on top of the retaining wall, and are delivered to the site with protruding reinforcement to tie in to the cast-in-place moment slab. Handrails, lighting columns and many other features can be accommodated. For further information see here