If a rural mail delivery vehicle is equipped with special signal lamps, there shall be displayed to the front two alternately flashing amber lamps located at the same level and mounted as high and as widely spaced laterally as practicable, and, to the rear, two alternately flashing amber lamps located at the same level and mounted as high and as widely spaced laterally as practicable. The lamps shall be of sufficient intensity to be visible 500 feet in normal sunlight, and shall be controlled so that they will only be used to indicate to other traffic that a stop is being made for the purpose of picking up or delivering U.S. mail.
(ILCS Ch. 625, Act 5, § 12-214) Penalty, see § 70.99