Whenever any vehicle is to be parked in any space adjacent to which a parking meter shall have been placed at any time during the period of limited parking as herein prescribed, the operator of such vehicle shall, upon entering such parking space, immediately deposit coins of the United States as shall be specified in the legend upon such parking meter. Upon the deposit of such coin or coins, and placing the meter in operation, such parking space may be lawfully occupied by such vehicle. If any vehicle shall remain in any such parking space for such length of time that the meter shall indicate by a proper signal that the lawful parking time shall have expired, such vehicle shall be considered as having been parked overtime, and the parking of a vehicle overtime shall be a violation of this article.