Each lot or parcel on a dead-end street turn-around or on a curved street, where the side lines thereof are diverging from the front to the rear of such lot or parcel, shall have a width of not less than fifty feet, measured along the building line established by the required front yard for the main building and between the side lines of such lot or parcel. (Ord. 5793-NS § 2 (part), 1987)