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

(4.54)
(4.55)
Motor •fl
A' ■ (P C C- P) and
Y2 13 14 ) *
Then referring to equations (4.51) and (4.52) the reduced form parameters
of the Ps and Cs are seen to be the elements of Table 4.32. .
Table 4.32
SELECTED REDUCED FORM PARAMETERS
Mode 1 iP J C
Rail
Variable
y b
l m
y b
2 m
y b
3 m
y b
4 m
ZZZZ
ylbr y2br
Z Z
y3br
Y4br
From this table we can see that the • reduced form estimates can be
utilized to derive estimates of the ratio of b m and b , and the ratios
of the yis.: It also illustrates the hazards of overidentification.
For each commodity group it is possible to derive four estimates of
b /b from the final set of regression equations. For our purposes we
M
shall use the simple average of the i P and ,C coefficients obtained
-
from the third set of estimating equations as our "best" estimate of
this ratio. As indicated previously, these ratios can also be used to
estimate the ratios of the elasticities of transport demand with re-
spect to the transport rates. 19
19. From Table 4.27 we see that
af r
Ob
mIL . —•and
r
Z af
m
Z •
139