In all zoning districts, vehicular garage doors shall only be permitted to face a private street, alley, side yard, or rear yard. On blocks within residential districts where the majority of structures on said block attain parcel access from a public street and existing vehicular garage doors face the public street, proposed vehicular garage doors may face, and be visible from, the public street. In said cases, no more than 25% of the building's front facade may be taken up by a vehicular garage.