In order to promote a living environment free from the excessive noise produced by vehicular traffic upon Interstates 35 and 80, the developer, with approval by the City Planning and Zoning Commission and City Council shall incorporate additional plantings, earth berming and proper acoustical site design techniques to reduce the negative impact of highway noise. As part of the final site development proposal for that area of the PUD adjoining Interstate 80 rights-of-way, sufficient landscape plantings, and earth berming barriers shall be provided; predominant plantings shall be of evergreen type, shrubs and trees, so as to assure year-round effectiveness; density and height of plantings or barriers shall be such as to provide attenuation. The incorporation of sound attenuation measures shall be the responsibility of the developer and made a part of site plan or plat improvements when affected properties are developed. (Ord. 786, 3-31-1986)