Yards. No principal building shall be located closer than 20 feet to the front property line. Required side yard setbacks are 15 feet. Each development shall be provided a rear yard of not less than 25 feet. Accessory structures, recreation facilities and on-site parking are all permitted in any side or rear yard, or within the front yard created by the main stem of an interstate highway or part of its ancillary ramp system, provided that no accessory structure shall project closer than 15 feet to any property line. These zoning provisions shall be inserted in Schedule A: Limiting Lot and Yard Sizes and Bulk Principal Building and Use.