This approach has been employed in two studies of the
deregulated general freight motor carrier industries: Blair,
Kaserman, and McClave in Florida, and Beilock and Freeman in
Arizona. In both studies pre and post deregulation rates were
examined across several routes, carriers, and weight and com-
modity classes. In both studies rate differentials between
commodity classes, which are in part based on value, were found
to persist after deregulation. These findings were cited as
supportive of the expedited service hypothesis.

 While Blair, Kaserman, and McClave's and Beilock and Free-
man's findings are consistent with the expedited service hypo-
thesis, they fall well short of being conclusive evidence for
two principal reasons. First, while there is no obvious reason
for hypothesizing that insurance costs would be abnormally high
in these markets, it cannot be stated with certainty what pro-
portion of the observed rate differentials are due to insurance
cost differentials or to expedited service cost differentials.
This failing is not particularly serious for two reasons.
First, as just stated, it is highly unlikely that insurance
costs in both the Arizona and Florida intrastate markets would
greatly exceed those found by Fauth for the nation as a whole.
Moreover, even if it is insurance cost differentials and not
expedited services which are responsible for these results, the
basic point still holds that price discrimination is not the
culprit.

 A far more serious criticism with using the intrastate
Florida and Arizona markets to make inferences about the source
of value-of-service price structures is that it is not entirely
clear that these markets are not operating as though rate bu-
reaus still exist. There are two reasons for suspecting this.
First, the habits of decades may not die over just a few years.
The fact that most carriers still employ the standard commodity
classifications in itself suggests a reticence to deviate from
long-established norms. One reason for such reticence in the
initial months after deregulation in Florida was that some