(6)   Preferential Parking.
Buildings with a principal use in the public, civic, or institutional, office, retail sales, commercial services, or vehicle and vehicular equipment sales and service use categories with 30 or more parking spaces shall designate at least five percent (5%) of the parking spaces for carpool, vanpool parking, and hybrid/alternative fuel vehicles. These preferential parking spaces shall be located closer to the principal building than other parking with the exception of accessible parking.