48 COMMISSION ON BUILDING DISTRICTS 



land bordering deep water constitutes in a city an almost certain dedication 

 to future terminal and industrial use. (See Figures 6, 23 and 24.) 



Rapid transit system 



While the location of the rail and water terminal facilities fixes the 

 location of industry of the heavier type, the passenger transportation system 

 is the chief factor in determining the location of business centers and sub- 

 centers and in determining the building up and the intensity of use of various 

 residential districts. The rapid transit system at present in operation or 

 under construction will necessarily determine the general lines of city growth 

 and development for many years to come. Owing to the automobile and 

 electric suburban railroad service, the local centers will continue to increase 

 within a radius of 50 miles or more of New York ; but the great bulk of 

 the population of the city will continue to be housed within a five-cent fare 

 and a 40-minute ride of the chief business center. (See Figure 25.) 



A time zone transit map was carefully worked out, showing the time 

 from every part of the city to the City Hall and to 14th Street. This time 

 includes the time required to walk from any given location served by a 

 transit line to the nearest station and the running time from that point to 

 the City Hall or to 14th Street. As a rule only the five-cent fare routes are 

 considered. Areas beyond half a mile or a ten-minute walk from a transit 

 line are not dealt with, as a half-mile belt is considered the limit of any 

 considerable influence of a transit line. The time zone map includes lines 

 planned and under construction as well as those now in operation, and is 

 based on estimated running time when the new dual subway system is in 

 full operation. (See Figure 26.) 



This time zone map was in constant requisition to assist the judgment 

 of the Commission in its determination of the appropriate use and the 

 appropriate intensity of use of particular areas. 



Vehicular traffic 



The main roads and thoroughfares are also of great importance in 

 determining the lines of future growth and development. The main roads 

 often fix the location of future transit lines and local business streets. To 

 determine the relative importance of existing traffic routes, traffic counts 

 obtained from the various boroughs were plotted on the city map. (Fig. 27.) 



Distribution of population 



The figures of the 1900, 1905 and 1910 censuses were charted on maps 

 by enumeration districts. These enumeration districts in Manhattan, The 

 Bronx and Brooklyn are generally very small areas including one or more 

 city blocks. The 1910 figures were even more carefully analyzed and dis- 

 tributed within each enumeration district according to the existing housing 

 accommodations. A spot map was then prepared with each spot representing 

 twenty-five people. This is probably the most intensive study that has 



