Required accessory off-street parking areas or truck loading space shall not be encroached upon by buildings, open storage, or any other use, except as specifically allowed on a limited basis as specified by the Planning Board during the site plan approval process. All such parking areas shall be provided with a turnaround so that vehicles are not required to back out into a street, except where otherwise specifically approved by the Planning Board for properties having access to minor streets and/or Town streets or highways.