The purpose of the PD Residential Districts is to establish a distribution of population density throughout the Township in relation to existing and prospective facilities, a convenient street system, employment areas and reasonable predictability of population growth. The standards are intended to offer maximum flexibility in site design and the selection of dwelling unit types in order to offer a balanced housing pattern attractive to all income and age segments of the community as part of the Township's fair share of meeting the region's low- and moderate-income housing need. In each of these districts, development design may follow either standard subdivision of lots or cluster zoning or, in the RS, R, R1, R2, CR, AH, RCA and PD Districts, utilize the planned development provisions of this chapter.