(a) Drivers of all vehicles in or on the premises shall drive in a careful and safe manner at all times and shall comply with the signals and directions of the police and all posted traffic signs.

(b) The blocking of entrances, driveways, walks, loading platforms, or fire hydrants in or on property is prohibited. Parking without authority, or parking in unauthorized locations or in locations reserved for other persons or contrary to the direction of posted signs, is prohibited. This paragraph may be supplemented from time to time by the issuance and posting of such additional traffic and parking directives as may be required, and such directives shall have the same force and effect as if made a part thereof.