SCALE .6

B. Suburban Passenger Rush Hour

Car Movement to and from

Chicago Terminals from 5 to 6 p.m.

Comparison of the routes taken by two groups of passengers is made in these two traffic maps.

A. Main Line Passenger Rush Hour

Car Movement to and from

Chicago Terminals from 7 to 8 a.m.

Each line represents 10 nrullion dollars' worth of petroleum products

American Petroleum Institute, N. Y. C, "Petroleum Facts and Figures," 1937.

C. Petroleum in United States Export Trade in 1936.

1. The representation of volume in this map is correct in that the general idea that Europe

receives most of the petroleum products of the United States is obtained.

2. As a method of graphic presentation it is incorrect in that two lines, or 20 million dollars,

is visually about three times as wide as one line, or 10 million dollars. The error is greater when there are just a few lines.

FLOW MAPS

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North Jersey Transit Commisiion, "Summary of 1926 Report, Rapid Transit for Northern New Jersey," January IS. 1926.

Diagram Showing Routing and Density of New Jersey Passenger Traffic to and in New York City in 1924.