Street Plan

Location of Streets. In planning a system of streets there are two objects that should be carefully considered; viz.: the drainage and easy communication between the different sec tions of the city. Not infrequently these elements have been overlooked or neglected. The surface drainage, the sewerage and the traffic must follow the general slope of the' land; and there fore if there is much irregularity of contour in the site, a location of the streets with reference to the contours will afford at once the best drainiage and the easiest communication between different parts of the city. If the site is nearly level, the relationship be tween the slope of the land and the direction of the streets is com paratively unimportant; but the arrangement of the street plan to afford the greatest. facilities for communication between the different parts of the city is still an important matter. Therefore the conclusion is that on a site of irregular contour the streets should be located with reference chiefly to the topography, and on a level site primarily to secure the most direct and easiest intercommunication.

Location with Reference to Topography.

Unfortunately in this country our very desirable rectangular system of public land survey has frequently led to the adoption of a very undesirable rectangular system of streets which, though convenient for dividing property into the greatest number of rectangular lots upon which can be built the greatest number of rectangular buildings. has little else to recommend it. Surface drainage sewerage and traffic should follow the slope of the country, and any attempt to deviate from this becomes a serious question in the building of a city upon any but nearly level ground. The streets are of necessity the drainage lines of the city and should be placed in the natural val leys, and the failure so to locate the streets in many cities where the land is very irregular in contour has red to in the construction of the streets and of a system of storm-water sewers.

The upper half of Fig. 82, page 311, shows an actual case of a system of rectangular streets located without any reference to the topography of the site; and the lower half of the same dia gram shows a proposed arrangement * that would save much ex pense in grading the streets and at the same time give a quick en trance into the center of the city, and also give long easy grades from the heart of the city to the higher outlying district.

Location with Reference to Directness of Communication. There are three distinct general plans for city streets with refer ence to directness and ease of communication.

One consists of a system of parallel streets crossing a sim ilar system at right angles. This is often called the checker-board system, but more properly the rectangular system, since the blocks are not necessarily squares. This arrangements gives the maxi mum area for blocks, and also furnishes blocks of the best form for subdivision into lots. The rectangular system is the most common, and has its most marked exemplification in Philadelphia.

A second arrangement of streets consists of the rectangu lar system with occasional diagonal streets along the lines of maxi mum travel. This system was employed by L'Enfant in planning t he city of Washington. Fig. 83 shows a portion of that city. To tt limited degree, the same plan was adopted in laying out the city of Indianapolis, which has four broad diagonal avenues converging to a circular park in the center. These two are the only cities of any importance in which this system was adopted in advance of building. This system is usually, but somewhat improperly vaned the diagonal system.

The chief advantage of the diagonal street is the economy to the saving of distance by traversing the hypothenuse instead of the two sides of a right triangle. In Rome, London, Paris, and In numerous other smaller places in Europe, whole districts have been razed to make way for new streets to serve as arteries for increased traffic.

A second, and by no means an unimportant, advantage of the combination of the diagonal and the rectangular system is the open squares and spaces so grateful to the eye and of no little sanitary value in compactly built cities. New York City has recently been spending a million dollars a year to create such spaces by purchasing the land and demolishing the buildings.

Although the diagonal avenue occupies ground that might otherwise be used for building purposes, there is a compensating advantage in the greater length of street front obtained.* In many cases the total cost of cutting diagonal streets through built-up districts has been paid by the increased value of the prop erty on and near the street thus opened up.

The third arrangement of city streets is the ring or con centric plan, which is very popular in Europe. The most noted example is Vienna with its Ring-strasse (ring street) within and its Giirtel-strasse (girdle street) without. The former is 187 feet wide and encircles the public buildings and the leading houses of business and amusement. The enclosed network of streets intersect the Ring-strasse at forty points, and outward from it extend fifteen main radial avenues.