The vertical moisture barrier (VMB) is an accepted form of treatment for highway pavements constructed on expansive clay. Many installations for rural highways in the United States and Australia have achieved great success in preserving the moisture regime in the pavement subgrade. As a result of this proven record, the method is increasingly becoming incorporated in some of the newly constructed pavements of new subdivisions in Australia. Nevertheless, many practitioners including some pavement design consultants, road contractors, and even Local Government Authority engineers, still question the technical validity of this application. Also, with the diminishing budgets of Local Authorities such serious allegations can lead to this method being completely ruled out as a measure of pavement management technique. Hence, it becomes necessary to establish whether it is the validity of this method that is under question or that of the allegations. The adaptability of this method ti the urban situation was investigated in a field trial at Horsham. Many challenges were faced during this process requiring proper address before a successful installation can be achieved. Two further locations, where vertical moisture barriers were installed, were also fully examined. The result of these investigations proves that the failure of these installations may be the result of either one or more of the following; invalid design of barrier, improper installation practice, lack of expert supervision and finally the absence of a good code-of-practice for vertical barriers. This paper addresses those issues relating to the major differences between rural and urban pavements affecting the barrier design and installation. It also provides a recommended practice for their design and construction.