Any commissioned police officer within the City or any employee hired by the City whose duties include parking enforcement is authorized to place a chalk mark on the tire of any vehicle parking in an area provided for in this Chapter in order to assist in determining the amount of time that such vehicle has been parked on the travel portion of the tire. The marking chalk shall be of a color which can be contrasted with the tire. It is unlawful for any person to erase any such chalk mark for the purpose of obstructing the enforcement of this Chapter. (Ord. 80-64 §1, 1980).