The city traffic engineer shall cause parking meters to be installed and maintained in all parking meter zones. Parking meters shall be installed upon the curb or sidewalk area immediately adjacent to each parking space. Each meter shall be placed in such manner as to show or display by a sign or signal that the parking space adjacent thereto is or is not legally in use. Each parking meter shall be set to display, after the operational procedure has been completed, a sign or signal indicating legal parking for that period of time conforming to the limit of parking time as indicated on the meter. Each parking meter shall indicate the limit of parking time in the parking space adjacent to the parking meter, and shall continue to operate from the time of the completion of the operational procedure until the expiration of the time fixed as the parking limit or a portion thereof for the part of the street upon which such meter is placed. Each meter shall also be so arranged that upon the expiration of such legal parking time it will indicate by a mechanical operation and by proper signal that the lawful parking period has expired. (Ord. 858 NCS §1; prior code §15.14.1.)