The Director of Public Works and the Town Engineer may jointly adopt, from time to time, such rules, regulations and specifications, within the limits of this article, for the conduct of the work to be performed under such permits as they may deem necessary to effectuate the provisions of this chapter. Such specifications may incorporate current approved standards and practices as the same may now exist or hereafter develop regarding dimensions and quality of curbs, sidewalks, combined curbs and gutters, stating the proportions and quality of materials to be used in various types of construction.