1. Front Yard. In all residential districts, there shall be a minimum front yard required as stated in the bulk regulations for that particular district; provided, however, where lots comprising 30 percent or more of the frontage within 200 feet of either side lot line are developed with buildings at a greater or lesser setback, the front yard requirement shall be the average of these building setbacks and the minimum front yard required for the undeveloped lots. In computing the average setback, buildings located on reverse corner lots or entirely on the rear half of lots shall not be counted. The required front yard as computed herein need not exceed 50 feet in any case. (See Section 165.20 for illustrations.)
2. Reduction of Required Yard or Open Space Prohibited. No yard or lot existing at the time of the effective date hereof shall be reduced in dimension or area below the minimum required by these zoning regulations. No part of a yard or other open space, or off-street parking or loading space provided about any building, structure, or use for the purpose of complying with the provisions of these zoning regulations, shall be included as part of a yard, open space, or off-street parking or loading space required under these zoning regulations for another building, structure, or use.