The license issued under this subtitle must be prominently displayed in the licensee’s storage facilities. A copy of the license shall be kept in each tow truck licensed under this subtitle. Each tow truck shall have painted on both sides of the vehicle or on a sign attached thereto, in a color which contrasts with the color of the body paint and in letters not less than 4 inches in height, the name, address, telephone number, and license number of the licensee. City Code, 1976/83, art. 15, §135(c), (d) Ord. 89-273