Off-street parking spaces shall not be required for any uses in the central business district as defined in Section 1139.02, which is exempted from the off-street parking regulations because it is impractical for individual stores in this area to provide individual parking spaces. An objective for the central business district is to encourage and maintain a compact grouping of retail stores and public and semipublic service buildings for the convenience of pedestrians using these facilities. For this purpose it is necessary to have businesses close together and not separated or scattered by individual parking areas serving only one building. Parking facilities for the central business district can best be provided by public parking areas and garages located according to a comprehensive plan.