STANDARDIZED STREET WIDTHS Mr. John Nolen F. A. S. L. A. Cambridge , Mass. If we are to remedy the municipal ills from which we now suffer, some large physical changes in American cities are absolutely necessary and inevitable. Nevertheless, perma¬ nent progress in city planning will not result usually from spectacular schemes for the sudden transformation of our cities, nor from revolutionary programs and proposals. Ad¬ vances will come more often from a patient but open-minded and scientific study of such problems as are represented by the title of this paper, followed by a close co-ordination of one subject with another in a comprehensive plan, thus rec¬ ognizing the unity of the city and the inter-relation of all its parts. It would not be difficult to convince anyone not already convinced — if such there be — of the importance of fixing street widths more intelligently and discriminatingly. At the present time an average of twenty to forty per cent of the total area of cities is devoted to streets, rising in the case of Washington, D. C., to fifty-four per cent. There¬ fore, even a slight variation in the width of the streets of a city becomes a matter of importance. Consider, for exam¬ ple what an excess of two feet in the width of the fourteen hundred miles of paved streets of Philadelphia would involve in the cost of land and paving! On the other hand — and here the lack of intelligent and discriminating action has even graver aspects — consider what the lack of a few feet in the width really necessary for streets in Philadelphia already P CITY PLANNING CONFERENCE involves! It involves directly the expenditure of enormous sums of money for street widening, or, indirectly, of much greater sums, practically incalculable in amount, as the pen¬ alty for conditions which still appear to our too timid minds virtually unchangeable. The evils of the present system of fixing street widths are acute. They demand prompt but careful examination and correction. What, then, are the causes of the existing diffi¬ culties in this matter of street widths and what are the reme¬ dies? Some ‘students of this subject are of the opinion that the evils are due, in part at least, to a standardization of street widths; to the fact that city councils or other munici¬ pal authorities have heretofore fixed upon a certain number of feet, usually forty, fifty or sixty feet, as the width for all streets. Undoubtedly such action has proved a handicap to many a city. But is the standardization itself the evil? Is it not the arbitrary and unintelligent character of that stan¬ dard; and is not the remedy another standard, or other standards, rather than the abandonment of the principle of standardization? Is there not danger of reacting too far, or of reacting in the wrong direction? The remedy for a stupid standardization of street widths is not likely to be found in the abandonment of all standards, but in the adop¬ tion of more intelligent standards. It would seem that street widths could be satisfactorily standardized because the facts upon which such widths rest are capable of definite classification and, furthermore, be¬ cause it is practicable to collect scientific data concerning these facts and from this data to reason to sound conclu¬ sions with a considerable degree of confidence. While these facts are numerous and varying, they are not more so than those connected with the cutting of metals, or some of the other operations that have been so successfully standardized in the industrial world in recent years. What are the facts which should determine street widths? They are (1) the width required for “ a line of vehicles,” thus fixing roadway units; (2) the width required for “ a CITY PLANNING CONFERENCE line of pedestrians,” thus fixing sidewalk units; (3) the clas¬ sification of the streets of a city according to the traffic re¬ quirements put upon them, or the other functions that they are to serve; and (4) an estimate of the present and future traffic of the streets of any given class, the width required to meet that traffic, and then the standardization of that width. (1) It is not yet possible to fix with scientific accuracy the width required for a line of vehicles, partly because the data as to the actual average width of present day vehicles is inadequate, and partly because that wfidth is just now in process of change, due mainly to the increasing size and use of the motor truck. Nevertheless, the conclusions on this point are already fairly definite. The difference is repre¬ sented by about one foot. One set of investigators holds that nine feet or thereabouts should be fixed as the width required for a line of vehicles. They base their opinion upon the fact that some motor truck bodies to-day have a width of eighth feet and that the tendency of manufacturers is to increase the width of trucks. The margin for safe clear¬ ance, taking into account average skill in driving, would require about another foot for each line of vehicles, making the total width nine feet. Other investigators find that to¬ day very few vehicles, even large motor trucks, measure more than six and one-half or seven feet in width, and that conditions of construction or laws are likely to place a limit upon advantageous width close to seven feet. This view has the support of some of the vehicle companies who hold, in the interest of the manufacturer and user of trucks, as well as the public, that six and one-half, or, at most, seven feet should- be the maximum width. It is not the purpose of this paper to try to settle finally the width required for a line of vehicles or, indeed, any other fact or specific point connected with the standardization of street widths. The purpose is merely to indicate the ad¬ vantages and necessity for such standardization and to sug¬ gest some reasonable basis for it. CITY PLANNING CONFERENCE But to apply further the method suggested above, we may assume for the sake of making the application definite, that a width of eight feet, the present working figure of many of the best practitioners, is sufficient for a line of vehicles. As a matter of fact, not only the width of vehicles but also the load is likely to be standardized by law, so that the engineer, landscape architect, or city planner will have a definite maximum figure to work with. These limits may have exceptions, but the exceptions should be discouraged b J a vehicle license tax, which would increase very rapidly on vehicles above certain dimensions. In addition to the space required for vehicles, allowance must be made on many streets for electric cars. Assuming double tracking, which is the most economical method usu¬ ally, this allowance should be not less than twenty feet. (2) Various methods have been devised and followed for determining the width of sidewalks. The most customary is to make the sidewalk some fixed proportion of the road¬ way. In some cases, following this method, each sidewalk is one-half the width of the roadway; in others one-third the width of the roadway. The latter appears to represent the most frequent practice. This method, however, appears arbitrary and, in some instances, would be unsound, because the use of the sidewalks does not necessarily increase and diminish with the amount of traffic on the roadway. How¬ ever, the custom of making the sidewalk one-third the width of the roadway has proved fairly satisfactory in practice. For example, in the subdivision of a one-hundred-foot busi¬ ness street into a sixty-foot roadway and twenty-foot side¬ walks. Fixing the width for a line of pedestrians at two feet, if the application of the principle to pedestrians does not appear too academic, this allows, on a street with a total width of one hundred feet, for ten lines of pedestrians on each of the twenty-foot sidewalks. The proper width of sidewalks, the method of determining that width, and a more rigid control of encroachments upon sidewalks, all deserve more attention than they have heretofore received. CITY PLANNING CONFERENCE (3) The classification of the streets of a city according to the traffic requirements put upon them or the other func¬ tions that they are to serve is, of course, one of the funda¬ mental requirements of any attempt to standardize street widths. European countries have made such classifications. Here are the figures for some of the cities of England and Germany. The London Traffic Commission made five divisions as follows: Main avenues.140 feet First class arterial streets. 100 “ Second class streets. 80 “ Third class streets. 60 “ Fourth class streets. 40 to 50 feet No street w r as to be less than forty feet. This standard classification, applying to London and its suburbs, is a great advance over the London Building Act of 1894, which put the average width of streets “ in the public interest ” at forty feet clear or twenty feet from the center of the roadway to the nearest external w T all; and the Council could not re¬ quire a greater width than sixty feet. The standard classification for German cities of the second size, cities like Leipzig and Frankfort, is as follows: Main thoroughfares.85 to 118 feet Secondary thoroughfares.50 to 80 “ Local streets.35 to 47 “ A Prussian law, in force since 1875, apparently drawn to meet the requirements of Berlin, fixes the following dimen¬ sions for the laying out of new streets and for the altera¬ tion of old ones: Main thoroughfares.95 feet or over Secondary thoroughfares.65 to 95 feet Local streets.40 to 65 “ The width of streets in different American cities varies greatly. There are very few that have adopted standards CITY PLANNING CONFERENCE for the classification of streets according to traffic require¬ ments. Probably the best classification is that of Washing¬ ton, D. C., which is as follows: Main thoroughfares.160 feet Secondary thoroughfares.120 “ Local streets. 60 to 90 feet The German city standards, given above, appear to be more reasonable and logical than those of London or Washington, and there is a distinct advantage in having more or less range within each classification, as against fixing the width hard and fast to a single figure. It ought to be practical to classify most of the streets of a city either as main thoroughfares, secondary thoroughfares, or local streets, and to apply to them one of the standard widths adopted for their respective classifications. (4) To determine such classification, however, requires an estimate of the recent and future traffic requirements of the streets of any given class. It does not seem wise to begin by fixing the width of a street at say fifty or sixty or one hundred feet, and then apportioning that width as favorably as may be between roadway and sidewalk. It is better to begin at the other end and try to decide what traffic capacity in roadway and sidewalk the street should provide for, thus determining which class it falls in; and then applying the unit of measurement adopted for car lines, for vehicles, for pedestrians, for trees, etc., decide upon the required width. For example, here are three illus¬ trations of this method: I. An average main thoroughfare is to have, say, A double track car line.20 feet 6 lines of vehicles, 3 on each side of tracks, 8 feet each ... 48 “ 20 lines of pedestrians, 10 lines on each of the two sidewalks, 2 feet each.40 “ Total for an average main thoroughfare.108 “ CITY PLANNING CONFERENCE II. An average secondary thoroughfare is to have, say, A double track car line. 4 lines of vehicles, 2 on each side of tracks, 8 feet each . . . 16 lines of pedestrians, 8 lines on each of the two sidewalks, 2 feet each. Total for an average secondary thoroughfare. 20 feet 32 “ 32 “ 84 “ III. An average local street is to have, say, Roadway for 3 lines of vehicles, 8 feet each.24 feet 12 lines of pedestrians, 6 lines on each of the two sidewalks, 2 feet each.24 “ Total for an average local street.48 “ These are only averages and are given simply as illus¬ trations of the method of standardization proposed and its application. The range of street widths for such a classi¬ fication might be as follows: Main thoroughfares . . Secondary thoroughfares Local streets. 90 to 180 feet 60 to 90 “ 40 to 60 “ Such a standardization would naturally differ from city to city as conditions and requirements differed. Its advan¬ tages would be twofold: first in fixing the range of normal street requirements of three or more important classes; secondly in definitely and consciously trying to determine in advance to which class a particular street belonged. Of course, even with such a classification there would be many, many exceptions, — special streets, having special require¬ ments and, therefore, calling for special provisions. But if no standards whatever are fixed — and this is the important practical point — there is danger that the normal differen¬ tiation of the streets of one class from those of another will be constantly overlooked, or that private interests through pressure and influence may succeed in securing ac¬ tion which is in conflict with the public requirements. It was largely to prevent these results that street width CITY PLANNING CONFERENCE standards, in most cases unintelligent and undiscriminating, were adopted by cities in the past. Where no standards whatever have been adopted many illustrations can be found of the abuses that have crept in, particularly the failure to allow sufficient street width for main and secondary thoroughfares. In the discussion thus far no reference has been made to trees, grass strips, or other planting in the streets, or of space set aside primarily for the adornment of the street or for insuring the benefits of light and air and an appear¬ ance of spaciousness. Such reference was omitted merely to simplify the subject and bring it within the compass of a brief paper. Of course, trees are desirable not only in residence streets, but also in most business streets. Of the many arguments against the greater use of trees in our business streets, the only sound argument in most instances is that there is no room for them. But as with traffic so with trees. The same method should be applied. If we are to have trees we must determine the width requirements of a line of trees, or two lines of trees, or whatever else is needed. Except for temporary effects, it is not good policy to plant trees in a space that is needed for roadway or sidewalks; nor is it good policy to plant one or more lines of trees in a space that is inadequate for their successful growth. If, for instance, it is decided that six feet is the minimum space in which a line of trees of a given species can flourish, then we should standardize that width for that species of tree and provide it. Exceptions there would be undoubtedly to standards for trees as for roadways and sidewalks, but they would be recognized as exceptions and justified because of exceptional conditions. Standards can only be applied profitably to the normal, but in such mat¬ ters as street widths five-sixths, perhaps nine-tenths, of all cases would be normal. The traffic and use of many city streets increase from year to year, tending to shift some streets from one classi¬ fication to another. How to provide a method of meeting CITY PLANNING CONFERENCE this increase is a difficult question to answer. To begin with, we must recognize that a city that is alive has growth, and that growth makes changes from time to time neces¬ sary. Street widths cannot be made right 64 once for all.” The utmost foresight must be exercised and then adjust¬ ments and widenings made to meet new conditions. Street development, like most other features of city planning, is an unending process. In the field of education, the unend¬ ing character of the process was expressed by the boy who inquired at a public library for a book which, he said, was entitled “ How to Get Educated and How to Stay So.” So it is with streets. The problem is how, by the exercise of skill and foresight, to design and arrange them to fulfill their functions and then from time to time how to re-design and re-arrange them to meet new requirements. In the case of streets where increased traffic is expected, the most prac¬ tical method of providing for it, perhaps, would be to re¬ serve some extra space between the roadway and sidewalk, or in the center of the roadway, or between the sidewalk and the buildings, utilizing this space temporarily as an area planted with trees and shrubs, or merely with grass. The evils that might follow from the adoption of an undiscriminating set of standards, or from an unintelligent application of a discriminating set, have not been over¬ looked. They might be serious. But it is my opinion that under our present city organization such evils would ordi¬ narily be less than those that almost inevitably follow from a lack of any established standards and from the policy of determining street widths piecemeal, as each is presented for decision. 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