It is this remarkable achievement of civilized man that to-day threatens to become ineffective. No sooner had the growth begun than it became clear that a keen rivalry between buildings and roads was inevitable, and further that unless the balance between these two were jealously maintained, the result to the road, so necessary to the life of our civilization, would be disastrous. The first half of the nineteenth century saw the passing of innumerable private Acts connected with roadmaking, and in 1848 the famous Public Health Act set up a considerable national machinery, since improved and extended by many later measures. The Public Health Act has, in point of fact, two objects. While the more important of these is to ensure the quick, safe and efficient development of the roads, the Act was also designed to ensure that the growth of new buildings should not, in its headlong speed, fall below a decent standard of strength, comfort and cleanliness. But all this time the road remains the special care of the authorities, for, while in their capacity of building controllers they merely inspect and sanction such work as is being done by private enterprise, they themselves undertake the making and mending of roads with increasing pertinacity. Nor would their work have shown the smallest sign of failure were it not for the abnormal and unregulated growth of our large cities, a growth which has now reached a stage at which the roadmaker must assume a measure of control if the traffic in our streets is to continue in motion.
The control of buildings is no new thing. In addition to the measures enacted to safeguard the integrity of the road-space we have had, for several centuries, the right to protest against a building being put up for a purpose that may be considered noxious. Not only has this right been enforced directly by means of legislation, but the State has made itself responsible for seeing that such undertakings as are entered into between landowner and tenant are carried out to the letter. If anyone proposed to erect a poison-gas factory in Grosvenor Square, his neighbours would have immediate power to restrain him, while a fruiterer’s shop could only be expelled if its owner were found to violate the conditions under which the land is granted. The law, however, upholds such conditions, and by these two means manages to exercise a considerable measure of user control, as it is now commonly called. Now, zoning is, by its very name, a comprehensive system of user control of this same kind. In so far, however, as it merely forbids the erection of a certain class of building in a stated zone, it can scarcely be said to influence architectural form. The true architectural importance of zoning lies in the fact that, the town-planner having failed adequately to control the height of buildings, it places in the hands of the roadmaker “emergency” powers enabling him to control their capacity.
He cannot, however, hope to do this justly and usefully without paying due regard to the use or function of each building at the same time that he inquires into its capacity, and this dual control is in fact the peculiar object of the roadmaker in his quality of zoning controller. Let me give an example of how he goes to work. It has been calculated by the committee which is preparing the development plan for the New York region that one mile of theatres is the cause of a daily traffic movement of 36,000 vehicles. The corresponding figure for a street of suburban shops is only one-fourth as high, while a mile of factories of ordinary size is responsible for a mere 600 vehicles. On the other hand, the rapid development of labour-saving machinery is daily increasing the output of modern factories, and has, during the last seven years, more than doubled the amount per worker of goods traffic going in and out of the average American workshop. In addition to the moving vehicles, the stationary ones, too, require to be considered, though a time is no doubt approaching when the parking of cars on public ground will be forbidden in most large towns. The worst aspect of this subsidiary problem is, of course, presented by places of amusement, whose audiences are acquiring the motor-car habit even more rapidly than the community as a whole. Not many years will elapse before American theatre and concert audiences habituate themselves to the motor-car to the exclusion of any other vehicle, and when this condition has been reached the mile of theatres already referred to will require a strip of land over a hundred feet wide along its entire length, in order to make room for the lines of waiting cars. Fortunately the motor-car has not yet attained such wide patronage in our own country, but anyone who will stroll down the narrow streets on the west side of Shaftesbury Avenue, say between the hours of eight and ten, on a week-day night, must conclude that with us also the difficulties are fast growing acute.
What is the solution to this knot of related problems? We can only reach it if we calculate the capacity of each building, multiply this figure by its traffic-producing coefficient, and then set this figure against the capacity of the surrounding streets. Difficult as these computations may appear, they yet are entirely feasible. Upon them is founded the science of zoning, a science which is as yet so imperfectly understood by the majority of us that it has been necessary to describe its origin and purpose in some detail. We may now go on to ask what is likely to be its effect on the architecture of the immediate future. The answer is one which may appear to contradict itself. Devised for the purpose of protecting the street from the undue growth of its buildings, the zoning ordinance must tend before all else to encourage the growth in size of the average individual building, and to grant it a measure of formal autonomy which will rapidly destroy the few remaining vestiges of coherent street design.
A height restriction, such as those in force in England, is founded upon a conception of civic order, but it may in addition have one of three practical objects. It may be designed to prevent unstable construction, or to ensure that the surrounding area is not unduly darkened, or to allow a jet of water to sweep over the roof in an outbreak of fire. The zoning ordinance is concerned with none of these things. Its object is to regulate capacity alone, and this it does by drawing an inclined line upward from the centre of the street, thus fixing an angle within which the outline of the building is forced to remain. Now, it is in the first place to be observed that rapidly sloping walls are as impracticable as they are unsightly in buildings of great height. It follows that the ordinance may best be complied with by breaking up the façade into receding vertical planes, each separated from the next by a narrow terrace. And the larger is the site occupied by a building thus falling back along a fixed angle, the higher this building will be allowed to reach, for in a triangle of which the angles remain constant the height will vary as the base. In the second place, a building measuring more than, say, sixty or seventy feet in depth will require an open area to provide it with an adequate supply of light and air. In a skyscraper of the old-fashioned type it was the custom to place this area at the centre of the building, which became a quadrangular box, encircling the four sides of a deep central void. But it is at its centre that a building erected under the zoning ordinance is allowed to reach its maximum height. To give up this part, more valuable than any other, for the necessary area would of course be folly, and the area is, in consequence, placed where the sacrifice of useful volume will be smallest, that is to say, at the periphery of the building, in such a manner as to lie open to the street.
A zoned building, consisting of an H-shaped arrangement of parallelepipeds with two external areas. The influence of the American zoning law is visible in the upper part only. It accounts for the stepping-back of the central block and the octagonal tower that surmounts each corner. (Fraternity Clubs Building, New York, by Murgatroyd and Ogden.)
