Analysis of the Vehicle Inventory and Use Survey for Trucks ... - About

Based on our knowledge of the general operational characteristics of the truck fleet, some data
were excluded in the various analyses based on the following criteria:
# if the empty weight, average weight, or maximum weight was reported as less
than or equal to 20,000 lbs
# if the empty weight was reported as more than 50,000 lbs
# if the average weight or maximum weight was reported as greater than 140,000
lbs
# where no value of a given attribute was reported
# if the empty weight exceeded the average weight or maximum weight.
Appendix E gives the detailed results for each year. Each page in the appendix represents one
cell in the matrix of 4 configuration types versus 13 body types. The population size of each
configuration/body type and the sample size, which indicates the number of survey records
analyzed, are shown at the top of the page. In addition, on the plots of empty weight, average
weight and maximum weight, the following statistics are given—sample size, population size,
population mean and population standard deviation. The annual VMT includes the population
size, population mean, and population standard deviation.
In Appendix E, all the graphs, except for the range of operation graph, were plotted in reference
to the percent of trucks in that particular configuration/body type. In other words, the Y-axis
represents percent of trucks or the cumulative percent of trucks. Range of operation differs
because the Y-axis is in terms of percent of total VMT for that configuration/body type.
In addition to the previously mentioned 8 characteristics that were analyzed, further analysis was
conducted on the distribution of average and maximum payload weights for each
configuration/body type. The results are presented in Appendix F. Payload weights were not
addressed on the survey. For this analysis, they were derived by subtracting the reported empty
(tare) weight from the reported average or maximum gross weights. The weight exclusions
mentioned before also applied to the payload analysis; however, one more exclusion was added
which did not allow the empty weight to be greater than the average/maximum weight.
Note: all weights and payloads are described in Kips (thousands of pounds) in both Appendices
E and F.
48