Within the BU, LI or LI-2 Zoning District, as an accessory to a conforming use, the Planning Board may approve the storage of up to 10 commercial trucks or vans up to 30 feet in length, where such vehicles are offered for rent or lease by the property owner, but such vehicles shall not be stored within any required front or side yard or any required rear yard abutting to a residential zoning district and any parking space or area used for storage of such vehicles shall not be considered toward meeting the parking requirement. The approval shall not require the submission of a site plan, except if determined to be necessary by the Planning Board following a site visit by reason of requiring mitigating controls, such as additional paving, screening, drainage, pavement striping, lighting or other necessary site features. In such a case, the Planning Board may require that a full site plan be submitted or may waive site plan requirements it deems unnecessary. Where a site plan is required, the Planning Board shall follow the procedures for approval of site plans including the advertising and conduct of a public hearing.