The National Academies Press

Currently Skimming:

Pages 85-108

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 85... ... 85 S e c t i o n 4 The third objective of HMCRP Project 07, to identify methodologies for analyzing the collected data, was achieved through a literature review and the development of a model that incorporates measures of accident performance. The literature review focuses on studies and reports that evaluate crash risk and the risk of transporting hazardous materials. Read the entire page →
From page 86... ... 86 then determined the likelihood that an en-route accident would occur in a year and developed an impact cost associated with each hazardous material class/division. Accident risk and cost per mile were calculated for each hazardous material class/ division. Read the entire page →
From page 87... ... 87 Large Truck Crash Causation Study (LTCCS) Analysis Series: Using LTCCS Data for Statistical Analysis of Crash Risk (Hedlund and Blower 2006) Read the entire page →
From page 88... ... 88 The variables in the risk equation above can be estimated from existing databases (FMCSA's MCMIS, PHMSA's HMIRS, NASS GES, or the LTCCS) Read the entire page →
From page 89... ... 89 where Yi = a binary dependent variable associated with the ith record where 0 represents a non-release event and 1 represents a release event. Xi = a vector denoting the values of l independent variables for the ith record: Xi =       1 5 1 2 1 x x x i i i ( ) Read the entire page →
From page 90... ... 90 study. This was achieved by compiling a data set consisting of PHMSA HMIRS reports, FMCSA MCMIS reports, and news articles over a 7-month period, estimating the total number of accidents per month, and calculating the average rate at which accidents occur. Read the entire page →
From page 91... ... 91 N um be r o f H ig hw ay H az ar do us M at er ia l A cc id en ts Figure 25. Highway hazardous materials accidents from March to September 2011. Read the entire page →
From page 92... ... 92 records that corresponded to 77 component-specific damage cases in which a component of the bulk package was damaged. On average, there were approximately 2.3 component-specific damage cases per accident. Read the entire page →
From page 93... ... 93 ability of a damage case release is determined by dividing the mean by the number of records considered in the initial odds ratio estimates (see Table 55) Read the entire page →
From page 94... ... 94 Variable n Mean p Odds Ratio Damaged Valve 74 0.068 0.09% 2.273 Damaged Lines, Pipes, and/or Fittings 74 0.108 0.15% 4.266 Damaged Manway 74 0.108 0.15% >999 Damaged Head 74 0.054 0.07% 0.163 Damaged Shell 74 0.622 0.84% 0.259 Damaged Weld and/or Seam 74 0.041 0.05% >999 Abraded 74 0.027 0.04% 0 Bent 74 0.095 0.13% 0.183 Burst or Ruptured 74 0.041 0.05% 1.087 Crushed 74 0.392 0.53% 0.176 Cracked 74 0.068 0.09% >999 Gouged or Cut 74 0.068 0.09% 2.273 Leaked 74 0.081 0.11% >999 Punctured 74 0.054 0.07% >999 Ripped or Torn 74 0.108 0.15% >999 Torn Off or Damaged 74 0.068 0.09% >999 Front Head Damage on Centerline 75 0.027 0.04% 1.000 Front Head Damage Above Centerline 75 0.053 0.07% 0.163 Rear Head Damage Below Centerline 75 0.040 0.05% 0.255 Rear Head Damage Above Centerline 75 0.013 0.02% >999 Bottom Front Driver-Side Damage 75 0.053 0.07% 1.666 Bottom Middle Driver-Side Damage 75 0.040 0.05% 1.087 Bottom Rear Driver-Side Damage 75 0.067 0.09% >999 Top Front Driver-Side Damage 75 0.053 0.07% 1.087 Top Middle Driver-Side Damage 75 0.027 0.04% 0.532 Top Rear Driver-Side Damage 75 0.080 0.11% 0.511 Bottom Front Passenger-Side Damage 75 0.040 0.05% 0.255 Bottom Middle Passenger-Side Damage 75 0.053 0.07% 0.163 Top Front Passenger-Side Damage 75 0.187 0.25% 0.969 Top Middle Driver-Side Damage 75 0.053 0.07% 1.666 Top Rear Passenger-Side Damage 75 0.080 0.11% 1.091 Damage to Piping and/or Undercarriage Below the Tank 75 0.133 0.18% >999 Passenger Vehicle Involved 77 0.273 0.35% 1.729 Heavy Vehicle Involved 77 0.065 0.08% 2.273 Crossed Centerline 77 0.221 0.29% 0.384 Ran-Off-Road 77 0.675 0.88% 0.500 Rolled Over 77 0.818 1.06% 0.439 Units Separated 77 0.195 0.25% 0.384 Struck Roadway 77 0.468 0.61% 0.778 Struck Ground 77 0.688 0.89% 0.397 Struck Concrete Barrier 77 0.065 0.08% 0.334 Struck Guardrail 77 0.130 0.17% 0.891 Struck Tree 77 0.013 0.02% 1.000 Involved Explosion or Fire 77 0.182 0.24% 8.333 Table 55. Distribution parameters of binomial variables and corresponding odds ratios. Read the entire page →
From page 95... ... 95 Significance Level Nominal Power Number of Cases Number of Accidents 0.05 0.70 274 120 0.05 0.75 308 134 0.05 0.80 348 152 0.05 0.85 398 174 0.05 0.90 466 203 0.05 0.95 576 251 0.10 0.70 209 91 0.10 0.75 239 104 0.10 0.80 275 120 0.10 0.85 319 139 0.10 0.90 380 166 0.10 0.95 480 209 Table 56. Sample size required for the variable "Thickness." Figure 27. Read the entire page →
From page 96... ... 96 Figure 28. Sample size requirements given ` = 0.10. Read the entire page →
From page 97... ... 97 standard (non-varying) thickness jacket adjusts the curve towards lower probability of release values by the same amount. Read the entire page →
From page 98... ... 98 ing the required sample sizes to the rate of data acquisition (see Table 59) Read the entire page →
From page 99... ... 99 theless, the following discussion details variable response completeness, summarizes the collected data, and provides a basic interpretation. In the pilot study, the design characteristics, commodity information, and accident information are stored so that one record pertains to one accident. Read the entire page →
From page 100... ... 100 als were involved, the bulk package was assumed to have at least two compartments. As a result, 40 accident records (80%) Read the entire page →
From page 101... ... 101 • Petroleum crude oil (UN1267) Read the entire page →
From page 102... ... 102 Damaged Components Similar to the damage locations, the bulk package components damaged in an accident were identified using the photographs accompanying newspaper articles and damage descriptions included in PHMSA's HMIRS "Description of Events" and "What Failed Description." Detailed information regarding the identification of the type of valve damaged in the accident is limited; therefore, for the purposes of this analysis, the following valve components were grouped together: • 106 -- Bottom Outlet Valve. • 107 -- Check Valve. Read the entire page →
From page 103... ... 103 Because damage to various components was identified using PHMSA's "What Failed Description," the pilot study estimates of component performance are expected to indicate a higher failure rate given that the component has sustained damage. A possible exception is the performance of the tank shell because the pilot study generally assumed shell damage on the ground-side of rolled bulk packages. Read the entire page →
From page 104... ... 104 Damage Type Damage type was identified for all 115 damage cases (see Table 65) Read the entire page →
From page 105... ... 105 a release of lading. This translates to a 58% probability of release per instance of damage. Read the entire page →
From page 106... ... 106 vehicle struck the bulk package and two records (4%) in which the bulk package struck another heavy vehicle. Read the entire page →
From page 107... ... 107 package vehicle was not driven out of the lane(s) of travel, 14 indicate collision with another vehicle. Read the entire page →
From page 108... ... 108 Roadway Ground Concrete Barrier Guard Rail Lighting/ Power Line Pole Bride Column Number Average Release Volume (LGA) Read the entire page →

From page 85...

... 85 S e c t i o n 4 The third objective of HMCRP Project 07, to identify methodologies for analyzing the collected data, was achieved through a literature review and the development of a model that incorporates measures of accident performance. The literature review focuses on studies and reports that evaluate crash risk and the risk of transporting hazardous materials.