The Manager may, when he shall determine that public safety or convenience requires the same, or that the movement of traffic will be expedited thereby, designate:
(a) Roadways as entrances to or exits from an Airport;
(b) Points where vehicles must come to a stop before proceeding;
(c) Places for crosswalks;
(d) Roadways as service roadways, public roadways or private roadways;
(e) Places where roadways shall be divided into lanes;
(f) The direction and manner in which vehicles shall proceed; and may erect signs, make markings and erect or place official traffic control devices and official traffic signals giving notice thereof, which sighs, markings, devices, and signals shall conform to the provisions of the Manual of Uniform Traffic Control Devices.