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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-after

studies