530 COMMERCE YEARBOOK
trucks have for the most part evolved a distinct field of transportation—that
 of the short hauls and the small shipments which are not
so profitable for the railways as other traffic, In many cases also
motor trucks serve as feeders for the railroads.
For further data as to automobiles and trucks see section on automotive
 products.

INLAND WATERWAYS

Aggregate River and Canal Transportation.
The total tonnage carried via our inland waterways, including the
navigable rivers and canals, without known duplication, aggregated
approximately 173,190,000 tons in 1924. The tonnage passing
through the Detroit River, connecting Lakes Huron and Erie was
80,074,000 tons. Of this 8,036,460 tons was local traffic. The navigable
 rivers of the United States accounted for 102,430,000 tons of
commerce, excluding through traffic of the Detroit River and all
other known duplication of cargo. These figures may be compared
with the volume of traffic by other channels of transportation (so far
as possible eliminating duplication of tonnage via any one means of
transport) as follows:

Tonnage originating on railways.
Overseas foreign cOMMEeree. oo mo cms
Great Lakes trade, eliminating trade between the United States
and Canada... _.____ mn
Trade between United States and Canada via Great Lakes_____
United States coastwise ocean-borne commerce (excluding Great
Lakes and Panama Canal)... .___. om
Total of navigable rivers and canals (excluding all known dupli-~
cation) ___._-.-__. SE) AEH te ess mR A
River transportation in the United States (excluding transit tonnage
 of Detroit River)... _ ___.___. .
Canal transportation in the United States__._. -
Sault Ste. Marie. _._._._.. cer mmm cem—————a
Panama Canal (intercoastal traffic only). _.____.

1, 188, 000, 000
82. 118. 000

83, 292, 000"
12, 930, 000

67, 678, 000
173, 190, 000

102, 432, 000
92, 290, 000
72, 037, 000
13. 527. 000

Great Lakes to Ocean Waterway.
The investigations of the Joint Engineering Board relative to the
Great Lakes-St. Lawrence waterway were continued during 1925
and are to be completed in 1926. The Board of Engineers for Rivers
and Harbors (War Department) began investigations, also, regarding
 a Lakes-to-the-Hudson waterway. The Department of Commerce
 inaugurated a survey of the principal economic questions involved
 in the Lakes-to-the-ocean waterway projects, which it is
expected will be completed about the same time as the War Department
 engineering surveys.