The director of transportation shall have the power and authority to alter, to maintain, to keep in good condition, to remove ice and snow therefrom, to remove posts, steps and any other obstructions therein, to regulate the placement, structure, and alteration of curbs constructed adjacent to state roads, to regulate the height, size, and shape of awnings, signs, and any other structures which project over all curbs and all sidewalks now constructed, in the process of construction or to be constructed on state roads; except, on portion or portions of state roads in cities or towns where the territory contiguous thereto is closely built up.
R.I. Gen. Laws § 24-8-9