Freight Mandatory Rule 11
With the cancellation of joint rates and the desire to receive quicker revenue settlements and remain
competitive, railroads are increasingly making use of this accounting rule which allows them to rebill
deregulated traffic. Apart from the rebill designation on the waybill, these waybills appear to be local
movements. Use of rebilling can be illustrated in the high portion of waybill movements which appear to
originate or terminate in the state of Illinois. Over the years, Illinois appeared to originate and terminate
more carloads than the west coast states of California, Oregon, and Washington combined. In actuality,
many of these movements involved long-distance traffic which was rebilled in Chicago. However,
estimates of true commodity length of haul may be understated. As transcontinental shipments are often
billed as two or more separate waybills, the Waybill Sample will not indicate a true representation of
mini-bridge movements, although it will provide accurate estimates of import or export traffic.
Freight Mandatory Rule 11 rebilling has the effect of overstating tonnage and units (car loads and
intermodal boxes) and understating the length of haul in the Waybill Sample. Each rebilled waybill record
in the sample double counts the tonnage and units of the originating waybill. Although the total distance
moved by rebilled traffic is captured in full, length-of-haul statistics are understated by showing a single
shipment as two, shorter-haul, shipments. Ton-mile statistics from the sample, however, are not affected
by rebilled traffic.
In order to determine the extent to which rebilling affects Waybill summary statistics, a methodology for
determining what traffic in the sample is rebilled must be devised. To this end, we extended a
methodology used by Manalytics, Inc. in a 1991 study on rubber-tired interchange.
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Preliminary analysis
using this methodology indicate that rebilling of intermodal units increased from 351,000 units in 1984 to
1,146,000 in 1994 (see Table 6). Over the same period, rebilled carload tonnage increased from five
million tons in 1984 to forty-five million tons in 1994 (see Table 7).
The implications of rebilled traffic in the Waybill Samples must be considered when using them for
analyses. For example, preliminary analysis of intermodal traffic from waybill samples for 1984 and 1994
indicates that the number of intermodal units moving 500 miles or less, increased by 1,006,000 units
between the two years. After adjusting for apparent rebilling, however, the volume increase in this
mileage block falls to 607,000 units. The same analysis shows that before adjusting for rebilling, the
number of intermodal units moving 2,500 miles and over, decreased by 42,000 units between 1984 and
1994. When adjusted for rebilling, the data indicate an increase in volume for this mileage block of
273,000 units (see Table 8).
Without recognizing, and adjusting for, an increase in rebilled traffic over time, growth and modal share
analyses will be biased, overstating growth and modal share in shorter lengths of haul and in total and
understating growth and modal share in longer lengths of haul. (Modal shares measured in boxes or
tonnage will be misstated whether classified by length-of-haul or in total. Measured in ton-miles, modal
share will be misstated when classified by length-of-haul, but not in total.) Conversely, should railroad
billing practices change due to mergers or changes in interline billing agreements and the trend in
rebilling reversed, growth for shorter lengths of haul and in total would be understated and growth for
longer lengths of haul would be overstated. Analyses that do not address the issue of rebilled traffic in the
Waybill Sample are likely to lead to erroneous conclusions.
Adjustment for Intermodal Carloadings
Intermodal traffic records captured in the Waybill Sample contain the number of intermodal units (boxes)
and the number of cars for the waybills sampled. Because much of intermodal traffic is billed at single
unit prices, some 90 percent of the intermodal records in the 1992 Sample were one box/one car
combinations, even where the car contained multiple platforms. Because of the one-to-one box-to-car