Comparison of certain variables in the large truck crash causation study with variables coded in a review of the trucks involved in fatal accidents case materials

Abstract

The Large Truck Crash Causation Study (LTCCS) is the largest and most ambitious effort to date to collect data on medium and heavy truck crashes. The purpose of the LTCCS is to identify and understand the factors that contribute to truck crashes in order to develop crash countermeasures that will be effective in reducing the number and severity of truck crashes. The University of Michigan’s (UMTRI) Trucks Involved in Fatal Accidents (TIFA) survey covers all medium and heavy trucks involved in a fatal crash. Nominally, all fatal crashes in LTCCS should appear in TIFA. LTCCS fatal crashes were matched to TIFA cases. Then the TIFA cases were re-examined independently, using the police report and any other information available, to attempt to code certain central crash variables in the LTCCS. The purpose was to determine the extent to which the central LTCCS variables could be coded using only the materials available in the TIFA survey. The results were mixed. At the highest level, agreement was quite good. Critical reason category agreed in 90.1 percent of the matched cases for which critical reason could be determined. Critical event category agreed in 86.1 percent of cases. However, there were higher rates of disagreement between LTCCS and TIFA at finer levels of detail and missing data rates were higher in the TIFA review cases. This result is not surprising in light of the much greater resources devoted to each case in the LTCCS project.