Nothing contained in this article shall be construed to prohibit commercial or public utility vehicles from using or occupying on-street public parking spaces as provided in this article, when such vehicles are actually engaged in authorized construction, maintenance or service activities to the highway, highway equipment or public utilities and such work is totally within the right-of-way of said highway; and provided that, such spaces are not otherwise lawfully occupied. In such cases, said vehicles shall not be required to make any deposit of coins in such parking meters so long as such construction, maintenance and service work is actively and obviously in progress.
In all other cases, such vehicles are subject to all of the provisions and regulations of this chapter. (1978 L.M.C., ch. 7, § 2.)