Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

the other monthly coefficients indicates the relative difficulty of ,
operating in that month. The changes between the months appear to .
establish a regular pattern. The winter months have negative.coef-
ficients, indicating difficulties of icing and bad weather. The spring
and early summer months have large positive coefficients, indicating
they are the easiest months in which to operate. Finally, the early
fall carries a negative coefficient due to low water (in genexal.there
is little rain in summer and so river depth falls). Again, these month-
ly variables could be used to redesign the rate structure to bring
prices in line with costs. .
Summary
A statistical production function for towboats on inland waterways
was estimated from data from three companies over a three-year period;
approximately 4500 observations on 100 towboats operating on 16 river
districts were used. Both linear and log-linear relationship were esti-
mated.
The reduction function for downstream operations was found to
differ significantly from that for upstream movements. It was also
found that the production functions differed between companies.
The productivity of a towboat (measured in terms of the number of
EBM's per hour produced) was regressed on the horsepower and also age
of the towboat, its crew size and whether it had Kort nozzles. Addi-
tional variables were the river in which it operated and the month and
year of the observation. Horsepower is a measure of the size of the
towboat and had a consistently positive, significant coefficient. With
the exception of one company, crew size had positive, significant coef-
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