ARRANGEMENT OF CITY STREETS.
Streets so far as possible should be systematically arranged and continuous throughout the extent of the city, both to facilitate travel and to admit of their being so named and numbered that the locality of a place of business or residence may at once be evident, from its address, to any one familiar with the general plan of the city. The rectangular system is desirable on this account, and also because it furnishes blocks of the best form for subdivision into building lots.
The proper arrangement of streets will always neces sarily depend in some measure upon the natural feat ures of the locality, and any system of arrangement will be more or less modified by local topography. Where for topographic or æsthetic reasons it may be considered desirable to use curved lines for the streets, the continuity and uniformity of arrangement should be maintained as far as possible. The use of curves on residence streets may sometimes be advantageous in reducing gradients or in its effect upon adjoining property through avoiding heavy earthwork. Where a change in direction is necessary the use of a curve usually gives a better appearance than an abrupt bend, unless the change can be effected at the intersection of a cross-street. Care is required, however, to prevent the local introduction of curvature disarranging the general plans and producing the chaotic condition due to an irregular use of short streets.
In laying out a rectangular system of streets the blocks ordinarily will preferably be long and narrow. The distance needed between streets in one direction is only that necessary to the proper depth of lots, while in the other direction the streets need only be Close enough to provide convenient communication for the travel and traffic. A convenient method would be to lay out the main streets so as to form squares large enough to permit the introduction of an intermediate minor street•through the blocks. These minor streets may then be introduced in the direction that seems advisable in each locality. Such an arrangement is shown in Fig. 28. The diagonal streets cut more space from the blocks traversed by them, but give more frontage and property fronting them will usually have more value than other property in its vicinity.
The proper location for diagonal streets intended as thoroughfares for traffic is naturally determined by the positions of the business centers or public buildings and parks, from which they may radiate in such manner as to bring the outlying portions of the city into the most direct communication possible.
A city cannot usually be laid out complete. Its for mation is a matter of gradual growth and enlargement, and the end cannot be seen from the beginning. For this reason it is frequently necessary to undergo great expense in the larger cities in cutting new streets or in changing the positions or dimensions of existing old ones in built-up districts in order to relieve the crowded condition of the streets, which hampers busi ness and renders travel difficult and unpleasant. Much of this difficulty might frequently be obviated if in growing towns and cities proper attention were given to the regulation of suburban development. Such development should be under municipal control so far as to require at least that each new subdivision which opens new streets should be made with a view to affording proper ways of communication between adjoining properties by making streets continuous. Where such regulation does not exist streets will be laid in any manner to best develop the particular prop erty in which they are placed.
A good example of the advantages of systematic and liberal plans in street arrangement, as well as of the evils of unregulated extension, is given by the case of Washington, D. C.
Fig. 29 shows a portion of the city of Washington illustrating its systematic arrangement. It consists of a rectangular system, together with two sets of diag onal avenues, and open squares or circles at the inter sections of the avenues.
Fig. 36 shows a number of suburban subdivisions on the borders of the city of Washington, made previous to the adoption of the law regulating them. In some cases the streets of adjoining subdivisions have no communication with each other, and the general ten dency is toward a labyrinth of short streets. The law now requires that all street extension within the Dis trict of Columbia shall conform to the general plan of the city of Washington; and under the operation of this law the lines of many of the city streets have been extended to all parts of the District, and all of the suburban development is being gradually brought with the city into one harmonious whole, on the same gen erous plan that exists within the city. The rectification of the irregular plats upon the borders of the city must, however, be a matter of heavy expense to the District.