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42 Hazardous Materials Transportation Incident Data for Root Cause Analysis Table 4-6. Proportion of cargo body type in MCMIS coded correctly, based on comparison with TIFA data. Cargo Body Type Frequency % Correct No cargo body (e.g., bobtail) 251 49.0 Van 5,432 71.9 Flatbed 1,713 70.1 Tank 1,011 77.7 Auto carrier 77 68.8 Dump 1,947 65.5 Refuse 288 64.9 cargo body types from the TIFA file, the number of such body types in TIFA, and the percentage identified correctly in MCMIS. Table 4-7 makes a similar comparison for truck configuration. The primary truck types, straight trucks with no trailer and tractor-semitrailers, are identified accurately 87.5% and 75.5% of the time, respectively. Less recognizable types like straight trucks pulling a trailer or bobtail tractors are less often accurately identified in MCMIS. Finally, Table 4-8 shows the percentage of selected variables that are coded the same in TIFA and the MCMIS Crash file. Variables shown in Table 4-8 are drawn from the FARS file and not from the TIFA interview. GVWR class in MCMIS aggregates the classes to 1 to 2, 3 to 6, and 7 to 8. The variable is left unknown in 62% of the cases, so the last row of the table shows the accuracy of the variable in MCMIS excluding unknowns. 4.1.12 Quality Control Process The MCMIS reporting methodology presents a difficult quality control process. First, there are a large number of jurisdictions filling out PARs that vary from state to state. Although many reporting agencies do not break down the reporting to the officer's level by providing a badge number, the 151,000 reports filed in 2005 were filled out by more than 61,000 agencies or indi- vidual officers. This means that, on average, a police officer from a specific agency might fill out less than three truck PARs in a given year. Assuming there are about 3,000 placarded shipments involved in crashes each year, the probability that a police officer will have to fill out a PAR for a placarded truck is on average, less than once every 20 years (60,000/3,000). This poses a signif- icant training problem if the officer will be filling out the hazmat supplement only a few times in his or her career. Requiring or sponsoring a formal training program in 50 states for an event that occurs a few times in an officer's career is probably not cost effective. Providing a guide to Table 4-7. Proportion of truck configuration in MCMIS coded correctly, based on comparison with TIFA data. Truck Configuration Frequency % Correct Straight truck 2,839 87.5 Straight truck plus trailer 373 42.9 Other straight truck 8 75.0 Bobtail tractor 175 61.7 Tractor-semitrailer 7,956 75.5 Tractor doubles 439 76.1