(a) Twenty-five (25) feet radius is adequate for passenger vehicles and shall be provided at minor cross streets where there are few trucks or at major intersections where there are parking areas.
(b) Twenty-five (25) feet or more radii should be provided at minor intersections or reconstruction projects.
(c) Thirty (30) feet radii or more should be used at major cross street intersections.
(d) Radii of forty (40) feet or more, three-centered compound curves or simple curves with tapers to fit truck paths shall be provided at intersections used frequently by buses or large trucks.