Off street parking. There shall be provided at the time of erection of any main building or at the time such buildings are altered, enlarged, converted or increased in capacity minimum off-street parking space with adequate provisions for ingress and egress by standard-sized vehicles in accordance with the requirements of this chapter.

Parking space requirements. Required number of off-street parking space for each use permitted by this chapter shall not be less than as follows:

Truck or commercial vehicle parking. No truck or commercial vehicle of a rated rate of more than one ton shall be parked on any street or on any residential premise in any R Zone for any consecutive period of more than four hours or more, provided that nothing shall prevent the parking of such vehicle in a fully enclosed garage or similar permanent structure.