Topic 3

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Topic 3 Safety Management Process Other
Steps CEE 763
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DIAGNOSIS
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DIAGNOSIS

• Objective
• to gain an understanding of crash patterns and
  causes so that potential countermeasures can be
  selected at the candidate sites
• Steps
• Safety data review crash statistics, collision
  diagrams,
• Assess supporting documentation
• Assess field conditions
• Identify safety concerns

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CRASH SUMMARY
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COLLISION DIAGRAMS
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SITE CONDITION DIAGRAM
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SELECT COUNTERMEASURES

• Objective
• Select countermeasures that can effectively
  reduce the crashes identified in DIAGNOSIS
• Steps
• Identify contributing factors
• Haddon Matrix
• Select countermeasures

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HADDON MATRIX
Example Haddon Matrix for Rear-end Crash
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CRASHES AT SIGNALIZED INTERSECTIONS

• Angle crashes
• Rear-end or sideswipe
• Left- or right-turn
• Nighttime
• Wet pavement
• Pedestrian/bicyclist

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CRASH MODIFICATION FACTORS (CMF)
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CRASH MODIFICATION FACTORS (CMF)
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CRASH MODIFICATION FACTORS (CMF)
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ECONOMIC APPRAISAL

• Benefit-cost analysis
• Change in crash
• Convert benefits to
• Estimate project costs
• Benefit/cost ratio
• Non-monetary considerations

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ECONOMIC APPRAISAL
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ANNUAL BENEFITS TO PRESENT VALUE

• Example What is the benefit cost ratio for a
  countermeasure implementation that will cost
  3,000,000, but with an annual benefit of
  872,400? Assume service life is 5 years and a
  rate of return of 4.

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PRIORITIZE PROJECTS

• Project prioritization
• Ranking by economic effectiveness measures
• Incremental benefit-cost analysis
• Optimization methods

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SAFETY EFFECTIVENESS EVALUATION

• Evaluation of the actualeffectiveness
• Observational Before-afterstudies