(a) Except in a period of emergency determined by an officer of the Fire or Police Department or in compliance with the directions of a police officer or traffic control sign or signal, when any vehicle shall be parked in any parking meter space alongside or next to which a parking meter is located, the operator of such vehicle shall, upon entering the parking meter space, immediately deposit or cause to be deposited in such meter such proper coin of the United States as is required for such parking meter and as is designated by proper directions on the meter, and when required by the directions on the meter, the operator of such vehicle, after the deposit of the proper coin or coins, shall also set in operation the timing mechanism on such meter in accordance with directions properly appearing thereon, and failure to deposit such proper coin, and to set the timing mechanism in operation when so required, shall constitute a violation of this section.
(b) Upon the deposit of such coin, and the setting of the timing mechanism in operation when so required, the parking space may be lawfully occupied by such vehicle during the period of time which has been prescribed for the part of the street or municipal parking lot in which such parking space is located; provided, that any person placing a vehicle in a parking meter space adjacent to a meter which indicates that unused time has been left in the meter by the previous occupant of the space shall not be required to deposit a coin so long as his occupancy of such space does not exceed the indicated unused parking time.
(c) If a vehicle shall remain in any such parking space beyond the parking time limit set for such parking space, and if the meter shall indicate such illegal parking, then, and in that event, such vehicle shall be considered as parking overtime and beyond the period of legal parking time and such parking shall be deemed a violation of this section.