Since the areas needed for public use can not be chosen without regard to the use and extent of private developments, it follows that some control over the use of private property--as by zoning--is an essential part of city or regional planning. When city planning is mentioned most people think first of streets. In this field the commission has been active in three ways--first, in an effort to make the streets fit the land and to follow along the hills and valleys instead of across them; second, in establishing a major thoroughfare system guiding the development of the main highways within the District of Columbia and extending the principles of the original L’Enfant plan to the limits of the District; and third, in securing public support of a regional highway system which will provide more adequately for traffic both into the city and between suburban areas. With the first of these aims in view many changes in the highway plan of the District have been made in cooperation with the District officials. These changes were advantageous to preserve natural topography, to fit the streets to property lines, to save trees, to provide drainage, or for like reasons. Several important street openings and widenings have been undertaken in accordance with the commission’s major thoroughfare plan, such as New York Avenue beyond the limits of the L’Enfant plan, the opening of a new Louisiana Avenue from the Union Station to Pennsylvania Avenue at Union Square, straightening of Michigan Avenue, and extension of Sixteenth Street to the District line. The plan which follows the recommendations of the commission has been recognized by the District officials in the adoption of a 5-year highway program. Several new regional highway projects are now complete or going forward in accordance with the regional plan. The Mount Vernon Memorial Highway and the Lee Boulevard establish new standards in highway design. The extension of Rhode Island and Massachusetts Avenues fits the plan. The Maryland-National Capital Park and Planning Commission has adopted practically all of the suggestions made by the Commission for the Maryland area as part of the Maryland master plan. Where parks are concerned the Commission has a special responsibility. The plans for parks both in the District of Columbia and out of it have received the indorsement of Congress in the Capper-Cramton Act. For the District the Commission is now acquiring parks of three types: (1) A parkway (the Fort Drive) around the city, 28 miles long and connecting the sites of the Civil War forts on the second row of hills; (2) a system of recreation centers and playgrounds distributed throughout the area in association with the schools and so far as possible providing a play area within a quarter of a mile of every child; (3) preservation of stream valleys and correction of the boundaries of Rock Creek Park.