Unused and unoccupied trailers, recreational vehicles, or boats may stand or be parked on private property if parked on a hard, drivable, impervious surface which does not exceed the current maximum allowable building lot coverage limitations for the zone in which the property is located. If such trailer, recreational vehicle or boat stands or is parked along the side of or in the rear of a residence, it must be adequately screened from adjoining properties and from the view of the right-of-way. Unused and unoccupied trailers, recreational vehicles, or boats in the front yard shall not obstruct the sidewalk or the sight distance triangle at a road intersection.