A preliminary engineering report for the Crosstown Expressway by consulting firm Modjeski and Masters proposes an eight-lane depressed route though South Street. “The Crosstown Expressway will serve as an effective buffer zone separating the proposed redevelopment areas to the north and the incompatible land usages to the south.” This mirrored the Philadelphia City Planning Commission's “Center City Comprehensive Plan,” referring to the Crosstown Expressway as the southern boundary of the central business district. The Crosstown Expressway was to serve as an important traffic artery for the city's planned 1976 Bicentennial celebration.