(1) The Department shall place and maintain all necessary traffic-control signs, signals, devices, and markings.

(2) Upon the written request of the chief administrator of a school and written approval from the superintendent or the superintendent's designee of the appropriate school system to the Streets Commissioner, the Department shall install and the school shall maintain a variable school speed limit sign subject to the approval of the Streets Commissioner. The criteria for approval by the Streets Commissioner shall include, but is not limited to: the volume and speed of vehicular traffic, age of school students, existing student paths of travel, existing school bus pick-up and/or drop-off locations, existing traffic signage and other appropriate traffic engineering factors. The written request shall specify the times of day, days of the week and months of the year when the flashing sign shall operate and such other information as may be required by the Department. The phrase "variable school speed limit sign" shall include, but is not limited to, a blank-out message, a variable message, or a message in effect during the operation of flashing beacons. The Department may establish a standard design or designs.[68]