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Accident Modification Factors for Traffic Engineering and ITS Improvements (2008) / Chapter Skim
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Pages 4-8

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From page 4...
... This measure of effectiveness is referred to as a crash reduction factor (CRF) or accident modification factor (AMF)
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From page 5...
... Accident modification functions rather than factors may be more appropriate. Several of the AMFs presented in this report are indeed functions.
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From page 6...
... • The AMFs reflect the impact of the improvement on different crash categories. Crash categories might include total crashes, severe-injury crashes, property-damage-only crashes, and specific crash types (such as rear-end and angle)
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From page 7...
... The safety knowledge documented in the HSM is being stated in terms of AMFs, and the HSM safety prediction tools include AMFs as a key component. Because the AMFs developed in NCHRP Project 17-25 are so closely related to the AMFs developed for and documented in the HSM and because the safety predictive tools for urban and suburban arterials and for rural multilane roads both require AMFs, this project and NCHRP Projects 17-26 and 17-29 were closely coordinated by the different teams, with information being shared on a regular basis.
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From page 8...
... • Chapter 3: Development of New AMFs through Analysis or Reanalysis of Crash Data includes a description of the treatments studied, the data used in the evaluations, the statistical methodology used, and the results of each evaluation. • Chapter 4: Development of New AMFs through Expert Panels includes a listing of the participants in each of the two panels, a description of the overall process followed for the two panels with respect to identifying and prioritizing the treatments to be explored, and the results of the panel discussions.
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Key Terms

  • treatment sites
  • injury crashes
  • expert panel
  • accident types
  • modification function

  • crash type
  • recommended amf
  • accident type
  • empirical bayes
  • accident modification

  • stop control
  • traffic volumes
  • modification factor
  • nchrp project
  • total crashes

  • amf based
  • single amf
  • traffic signal
  • safety evaluation
  • safety performance

  • safety information
  • highway safety
  • crash data
  • predictive certainty
  • nchrp projects

  • safety effects
  • develop amfs
  • rural multilane
  • existing amfs
  • multilane roads


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