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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 26 Schedule
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 27 Deliverables Methodology for cost-benefit-risk tradeoff analysis Evaluation of literature Characterization of experience of resident engineers Recommendations of factors and measurement endpoints Identification of options for site selection and upgrading, including the two phases of screening and evaluation
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 28 Deliverables (cont.) Databases and demonstration of the above methodology Documentation of the automating spreadsheets Interim and final reports, presentations, and automating spreadsheets Maintenance of an internet web site
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 29 Review of Comparison Tool
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 30 Motivation Tools are needed to equitably balance: –Crash reduction, –Capacity improvement, and –Project cost –Other factors To aid in the decisions of what roadway-projects to undertake with available funds
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 31 Project Objective Our objective is to provide tools to assist the Virginia Department of Transportation in improving the comparison in planning of potential roadway improvement projects.
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 32 Criteria Included in Comparison Safety Aesthetic Value Cost Performance Environmental Concerns Explicitly Quantified Implicitly Addressed Economic Development
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 33 Daily Traffic Travel Time Saved per Vehicle Total Travel Time Saved Crashes per Year Crashes per Vehicle Crashes Avoided per Vehicle Crashes Avoided per Year Lives Lost, Injuries Comparison-Tool Options Right of Way Preliminary Engineering Construction Engineering Life Cycle Length of Road-Section RISK PERFORMANCE COST
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 34 Intuitive Graphical Representation Crash risk reduction Performance gain Note: Icon area is proportional to project Cost.
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 35 Precision of the Assessment
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 36 Cost Crash Risk Reduction Performance Gain
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 37 Sample of Database of Richmond District (from Travis Bridewell)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 38 Database of Richmond District
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 39 Literature Review Guiding principles ~ King (1995) Prioritization technique ~ Pigman and Agent (1991), Caldwell and Wilson (1999) Cost-effectiveness approaches –AASHTO Roadside Design Guide (1989) –Mak (1995) –Glennon (1974)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 40 Literature Review (cont.) Warranting Methods –Charts –Flow charts –Guidance tables and figures Experiences of traffic agencies –New York –Ohio –California Survey of State DOTs –Minnesota –Wyoming –Alaska
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 41 Guiding Principles (1)Remove hazard (2)Relocate hazard –Lower probability of a collision (3)Make the hazard forgiving –Crash cushions –Breakaway Use guardrail only when all other options eliminated Alert motorist to any hazard, i.e. flashing lights, warning signs, rumble strips, etc. King (1995) (From Travis Bridewell)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 42 Prioritization Technique Procedure used to identify and rank locations for guardrail installation and replacement Uses a hazard-index point system Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 43 Pigman and Agent (1991) 1. Development of critical numbers and rates of run-off-road accidents 2. Preparation of list of locations with critical rate of run-off-road accidents 3. Development of hazard-index point system 4. Conduction of a field study 5. Tabulation of hazard-index points 8. Analysis of cost-effectiveness 7. Determine improvement benefits 6. Determination of improvement costs
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 44 Steps of Technique (1)Development of critical numbers and rates of run-off-road accidents A c = critical accident rate; A a = average accident rate; K = constant related to level of statistical significance selected (K=2.576 for a probability of 0.995); M = exposure (for sections, M was in terms of 100 million vehicle-miles, for spots, M was in terms of million vehicles Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 45 (2)Preparation of list of locations with critical rate of run-off-road accidents (i.e. list of locations with critical rate factors greater than 1.0) (3)Development of hazard-index point system Steps of Technique Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 46 Hazard-Index Point System 1. Number of run-off-road accidents15 2. Run-off-road accident rate15 3. Traffic volume10 4. Speed limit or prevailing speed10 5. Lane and shoulder width10 6. Roadside recovery distance10 7. Embankment slope10 8. Embankment height10 9. Culvert presence5 10. Subjective roadside hazard rating5 Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 47 Step of Technique (cont.) (4)Conduction of a field study –Data collection on locations with critical rate factors greater than 1.0 (5)Tabulation of hazard-index points –Develop a list of locations in decreasing order in order to identify a manageable number of locations on which a cost- effectiveness analysis can be performed Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 48 Step of Technique (cont.) (6)Determination of improvement costs (7)Determine improvement benefits –Accident reduction factors –Severity indices Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 49 Step of Technique (cont.) (8)Analysis of cost-effectiveness –Listing of locations in decreasing benefit-cost –Optimization of budget Pigman and Agent (1991)
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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 50 Inputs for Budget Optimization Number of locations to be analyzed Budget levels to be considered Costs assigned to each accident severity Interest rate Traffic growth rate Accident history Alternatives for reducing accidents Expected improvement life Improvement cost Annual maintenance cost Expected reductions in accidents due to improvements Pigman and Agent (1991)
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