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76 Hazardous Materials Transportation Incident Data for Root Cause Analysis 4.5.8 Analyses Using Database The LTCCS raw dataset was presented to the analytical community in 2006 and numerous analyses have been performed on the dataset. The analyses presented here will focus on the haz- mat truck accidents. Table 4-22 shows the breakdown of hazmat shipments included in the LTCCS. If a reportable quantity was being shipped, then the shipment would have to be plac- arded. There are only 40 placarded vehicles analyzed in the LTCCS. Table 4-22 shows that slightly more than 40% of the reportable shipments, 17, were Class 3 materials. Class 2 was the next most common, with 8 vehicles out of the 40, about 20% of the total. Thus, Class 3 and 2 shipments make up more than 60% of the total hazmat vehicles included in the LTCCS. For the 40 reportable accidents, the database can be queried to look at health factors, as shown in Table 4-23. Of the health factors listed in Table 4-23, other than requiring corrective lenses, almost all of the entries identify no health factors that might have contributed to the accident. To get better statistics for health issues that could affect safety would require a health assessment to be col- lected for at least 400 or more hazmat incidents. With 400 drivers, it might be possible to address the contribution from heart attacks. More than 1,000 would be required to get valid statistics on less common health conditions. This implies that if driver health is a contributing cause, it prob- ably has to be captured in all hazmat truck accident records, as it was a few years ago in MCMIS, and for some reason has been left blank in MCMIS beginning in CY 2002. Drug use by the driver also was tabulated. In the 40 drivers hauling hazardous materials, there were 10 drivers taking prescription drugs and 6 taking over-the-counter drugs. There were no instances where the driver was taking illegal drugs. In the 40 accidents involving a hazmat vehi- cle, in three of the accidents, the driver of the other vehicle was believed to be taking illegal drugs. A drug test verified the presence of the drug in one case and in the two others, the results of the drug test was unknown. Table 4-22. Types of hazardous materials included in vehicles in LTCCS. Reportable Quantity Specified in 172.101 Hazardous Material Table [49 CFR 172.101] Material Yes No Unknown 2.1 Flammable Gas 5 1 2.1 LPG 1 2.2 Nonflammable Gas 2 2 3 Combustible Liquid 5 3 Flammable 12 3 2 4.1 Flammable Solid 1 4.3 Dangerous When Wet 1 5.1 Oxidizer 1 6.1 (Liquids) 1 1 6.1 Zone A 1 8 (PIH) Zone A 1 8 Corrosive Material 6 1 9 (Elev Temp Materl) 1 9 (Hazardous Waste) 1 9 Miscellaneous HM 1 1 Total 40 9 2
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Database Analysis 77 Table 4-23. Listing of health factors present for vehicles in LTCCS containing hazardous materials. Health Factor Total Health Factor Total Illness Factor Count 1 Astigmatic 2 Heart Attack 1 Other Vision 6 Epileptic Seizure 0 Unknown Vision 7 Diabetic Blackout 0 Other Factor Count 1 Other Blackout 0 No Factors 32 Cold Flu 0 Hearing Impairment 0 Other Illness 1 Prosthesis 0 Normal Vision 17 Paraplegia 0 Legally Blind 0 Strenuous Recreation 0 Myopic 5 Strenuous Non-Work 1 Hyperopic 4 Sleep Apnea 0 Glaucoma 0 Other Factor Physical 0 Color Blind 0 The ENVIRONMENT Table provides a lot of information that is useful for defining the char- acteristics of the accident location. Table 4-24 shows the relationship between the JUNCTION and INTERCHANGE parameters for the 40 placarded trucks included in the LTCCS dataset. As shown in Table 4-24, the data are internally consistent. There are no entries with INTERCHANGE = Yes that are not entered under a JUNCTION category related to an inter- change. The data also show that of the hazmat truck accidents, more than 25% (11/40) occur at interchanges. Table 4-25 looks at the same data using the parameters INTERCHANGE and FUNCTIONAL_CLASS. Table 4-24 shows that the 11 hazmat trucks in the LTCCS with INTERCHANGE = Yes are all associated with Interstate highways. Table 4-25 shows that there are also 16 additional accidents on Interstate highways not associated with interchanges. This means that of the 27 crashes involving hazmat trucks, 40% of the accidents are at interchanges. Given that interchanges occur only every few miles, on a per mile basis, accidents at interchanges on Interstate highways clearly dominate. Although one might be tempted to look at the ratio of urban and rural freeway accidents from these data (2 rural and 25 urban), the fraction of the miles driven in urban and rural areas is not known. Thus, it is difficult to infer an accident rate from these data alone. In HMIRS, the origin and destination of the shipments is shown and if these data could be matched with HMIRS records, it would be possible to derive an estimate of these rates. There is another factor that could enter into the analysis as well. In the LTCCS, the accidents were not selected randomly; they had to be close to the location of 17 accident investigation teams and, as a result, the acci- dents selected could be biased toward urban accidents. Table 4-24. Relationship between junction and interchange in LTCCS. Interchange Junction No Yes Entrance/exit ramp related 1 7 Intersection 2 Intersection related 2 Non-junction 22 Other location in interchange 4 Rail grade crossing 2