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PHYSICAL AND OTHER CONDITIONS THAT HAVE

COMPLICATED STREET TRAFFIC IN CHICAGO

As one views the city of Chicago today with its magnificent parks, its beautiful boulevards, its astounding masses of business structures, and its hundreds of miles of delightful residence streets, he sees one of the world's greatest monuments to the ingenuity of man. The builders of Chicago during the past century wrought out of unpromising wilderness a giant metropolis. They worked well according to their knowledge. That in all cases they did not plan wisely is in no manner to their discredit, for it was impossible for them to foresee the ultimate magnitude of the city and many of the problems which would confront it. Happily the citizens of the present generation, being in a better position to see the current of progress, have the foresight and initiative to correct the mistakes of the past, and to remove the obstacles that keep the city from its fullest destiny.

RESTRICTIONS CAUSED BY LAKE MICHIGAN

All who have analyzed the prosperity of Chicago must realize that the location of the city on a great inland sea has been one of its most strategic advantages. Thus situated it has become a focal point for both land and water transportation. Moreover, the lake has an important effect upon the city as a desirable place to live, adding beauty to its parks, recreation for its citizens, and a moderation for its climate. The fact, however, that Chicago has developed on a semi-circular plan instead of in a full circle has a very complicating effect upon its system of traffic and transportation. Had it been possible for it to have spread out in all directions from a common center, its great population could have been distributed within a much smaller area. Length of travel from home to work or shopping would have been much less for the average citizen. Moreover, traffic agencies with their focal point in the center of the city would have been able to approach their destination over approximately twice as many arteries as those which are available with the existing development.

Chicago's semi-circular pattern emphasizes the difficulties experienced in traffic control and renders more urgent the requirement that every method of facilitation should be employed. It has always been the habit of Chicago to capitalize its difficulties, and it is possible that the handicap placed upon traffic distribution by the lake may ultimately be a blessing in the opportunity which it affords for the construction of a large-capacity, high-speed outer drive. While the Survey has not been engaged in a consideration of the city planning requirements in the city, it is impossible to avoid the conclusion from the materials collected, that no single improvement could be of greater advantage from a street traffic standpoint than the early completion of an out-drive the entire length of the city's twenty-two mile lake front.

THE EFFECT OF THE CHICAGO RIVER ON TRAFFIC CONDITIONS

Two physical conditions which always complicate street traffic movements are hills and waterways. The former must be detoured, cut down, or tunnelled to permit easy flow, and the latter must be provided with adequate bridges. Chicago has no hill difficulties, but its river problem has been a long and irritating one. There are few central districts in any city that are so completely hemmed in as is the district in Chicago by the river on the north, the west, and to some extent on the south.

Figures have already been given to indicate the amount of restriction to traffic resulting in the river bend to the south. (See Table 8.) The Street Traffic Committee is fully in sympathy with the efforts toward river straightening which are being carried on at the present time. Its immediate interest, however, is in those uses and regulations of the streets which tend to hamper or facilitate the movement of traffic.

The bridge situation would be sufficiently serious around the central business district if all of the existing structures were constantly available for use. Even under such conditions all of the natural connections for the district could not be used to their full capacity for all of them are not carried across the river by bridges. A bad situation has been aggravated by the use of movable bridges.

Insignificant movements of freight along the river are permitted to block the most important arteries of travel in the city, and to cause delay and inconvenience to thousands of citizens for negligible saving

to transportation agencies and shippers. The press of the city has carried many heated articles on the subject and printed numerous pictures of congestion resulting from bridge openings. At the risk of unnecessary duplication Figure 18 is incorporated, as illustrative of a typical delay caused to traffic on Michigan Boulevard by an opening of the Link Bridge. The picture was taken at eleven a. m. which

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Delay Resulting from an Opening of the Link Bridge

is not a rush traffic hour. The opening of the bridge was occasioned by the movement of a single box car on a barge.

Something of the total delay to traffic resulting from bridge openings is indicated by Table 14, for which the Survey is indebted to the city harbor master. This shows that during the year ending June 30, 1926, the streets of the central district were blocked 35,351 times for an average of approximately 3.5 minutes. The total obstruction of 121,953 minutes is equivalent to 2032 street hours, or 254 eight hour street days.

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1 Adams Street bridge has been out of service since September 30, 1925, due to building of new bridge. For the above information the Survey is indebted to the Department of Public Works.

The ultimate solution of the delay now existing along the river is to be found in the adoption of some type of fixed bridge policy. It is probable that under existing conditions a complete fixing of the bridges would cause an unwarranted hardship to the industries that depend upon river transport, but some more equitable balance between these requirements and the demand for free street use should be reached. Limitation upon the openings of bridges should be more accurately adjusted to traffic and transportation demands as they are revealed by a study of street use. Attention is called to Fig. 19 which shows the volume of vehicles entering and leaving the central business district during the hours of a normal week day.

The present ordinance respecting bridge openings on streets leading to the central district places a prohibition between the hours of 6:30 and 9:30 a. m. and between the hours of 4:30 and 6:30 p. m. These hours may have been justified when the ordinance was drafted in 1913, but they no longer adequately apply. The study conducted by the Survey indicates that heavy movement into the

Period

in 30-minute

of Vehicles

Number

2000

district over the bridges does not begin until 7:30 a. m. and that the morning peak has substantially declined by 11:30 a. m. Present conditions would seem to require that the morning prohibitions should at least include these hours. The afternoon prohibitions as they exist at present, that is from 4:30 to 6:30 seemed to fit fairly accurately the peak demand for street use and do not indicate the same urgency for extension.

12.000

11 000

10 000

9000

8000

7000

6000

5000

4.000

3000

TOTAL NUMBER OF VEHICLES

CROSSING BRIDGES IN CENTRAL BUSINESS DISTRICT
TYPICAL WEEK DAY - MAY 1926

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A second relief which should be sought is in the prohibition of bridge openings at any hour of the day to river craft of insufficient size and importance to warrant the expense and delay involved. Federal authorities can not reasonably be adverse to conservative limitations along these lines.

As another type of relief available in the near future it should be pointed out that Wacker Drive, being a marginal street along the south bank of the river can serve to materially lessen delay to north

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