The National Academies Press

Currently Skimming:

Pages 9-25

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 9... ... 9 The ISPE evaluation measures addressed by this report rely on collecting a census of crashes, that is, all the reported crashes that occur in a predefined geographical area during a predefined time period. A census avoids the problem of random sampling by collecting all crashes. Read the entire page →
From page 10... ... 10 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data reduction is generally done at the onset of data assembly. The order of case reduction and the number of cases reduced in each step should be captured and documented, so that the results of the ISPE can be validated by a third party. Read the entire page →
From page 11... ... ISPE Study Design 11 explicitly used within these procedures. This crash record number allows for reference to be made to the original records by the jurisdiction that maintains those records if necessary. Read the entire page →
From page 12... ... 12 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data reported, but the record number is unknown, a value of 99 is entered in this field. If the crash is unreported, a value of 00 is entered. Read the entire page →
From page 13... ... ISPE Study Design 13 • Possible Injury (C) : A possible injury is any injury reported or claimed that is not a fatal, suspected serious, or suspected minor injury. Read the entire page →
From page 14... ... 14 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data vehicles that will likely not be addressed in the development of safety features but nonetheless may be exposed. The equivalence of MMUCC data set codes for the category of vehicle body type is shown in Table 1. Read the entire page →
From page 15... ... ISPE Study Design 15 The equivalence from crash reports and crash databases is believed to be straightforward. In situations in which the jurisdiction does not use either the MMUCC or FHWA vehicle classifications, equivalence should be made and documented by the analyst. Read the entire page →
From page 16... ... 16 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data also be used when the vehicle experiences a secondary impact with the same terminal or crash cushion. • OTR: The vehicle experiences a harmful event after the impact with the safety feature and the nature of that event is known but is not captured by one of the codes listed above (e.g., fire or immersion in water) Read the entire page →
From page 17... ... ISPE Study Design 17 represents "true" and the number zero (0) represents "false." The value is true when the SFUE is involved in at least one event in the crash sequence. Read the entire page →
From page 18... ... 18 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data undertaken, this field may also be determined through inspection of the crash scene. When the value for this field cannot be determined, a value of 99 is entered. Read the entire page →
From page 19... ... ISPE Study Design 19 (when the ICP is unknown) is determined from the police report or database for each crash. Read the entire page →
From page 20... ... 20 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data A second example is cable barrier. A jurisdiction may have several different manufactures of high-tension cable barrier (i.e., NAME) Read the entire page →
From page 21... ... ISPE Study Design 21 Column Field Name Definition Format A SFUE Safety feature under evaluation 1, 2, 3, 4, 5 as text B CRN Crash record number Varies by jurisdiction, or 99 or 00. C CRASH_DATE Date of crash YYYYMMDD or 99 D TOTAL_UNITS Number of units involved in the crash Number E MAX_SEV Maximum severity of the injuries to the occupants of the impacting vehicle. Read the entire page →
From page 22... ... 22 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data It may be desirable to maintain additional fields within the data set; if so, these fields should be included to the right of the fields shown in Table 3 (i.e., to the right of Column T) Read the entire page →
From page 23... ... ISPE Study Design 23 are made, and insurance claims are processed shortly after a crash. The guidelines in this report distinguish between routine and investigative ISPEs. Read the entire page →
From page 24... ... 24 In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data Recommended Sample Size (n) , by Precision (w) Read the entire page →
From page 25... ... ISPE Study Design 25 Table 5. Recommended sample size for investigative ISPE at 90% confidence interval. Read the entire page →

From page 9...

... 9 The ISPE evaluation measures addressed by this report rely on collecting a census of crashes, that is, all the reported crashes that occur in a predefined geographical area during a predefined time period. A census avoids the problem of random sampling by collecting all crashes.