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Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 101 Wyoming DOT Place guardrail when there is a fill slope of.

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Presentation on theme: "Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 101 Wyoming DOT Place guardrail when there is a fill slope of."— Presentation transcript:

1 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 101 Wyoming DOT Place guardrail when there is a fill slope of 3:1 or steeper located within the clear zone Their clear zone requirements match the AASHTO guide

2 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 102 Alaska DOT Developed a spreadsheet for conducting a cost- effectiveness analysis on variant obstacles Supplements the AASHTO Roadside Design Guide Returns an accident prediction output and a project cost output Used to provide relative estimates for comparison of alternatives, not to determine an exact cost for accidents

3 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 103 Survey of State DOTS

4 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 104

5 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 105 Summary 50 states contacted via email or web submission forms 17 responses as of February 9 Expecting responses from a few additional states (Alaska and Ohio)

6 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 106 Who deals with Guardrail Personnel/Divisions with expertise on funding allocation for guardrails Maintenance Division referred to most often Others: Roadway Design Policy and Budget Design engineer Traffic engineer Highway Safety engineer State Traffic engineer Highway Operations

7 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 107 Recommendations from DOTs Variety of responses: –Benefit-cost ratio or other cost-effectiveness analysis –Guardrail projects done in conjunction with other scheduled projects –Compare guardrail accident rates to total accident rates and prioritize based on guardrail accident rates –Look at high accident areas first, high ADT areas second –Follow AASHTO 350 implementation Task Force summary Some states noted that they too are in need of assistance in this area

8 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 108 Databases Utilized 6 respondents have some sort of guardrail inventory Information included: –Amount of guardrail installed –Guardrail type, end treatment, location, length –Information on completed guardrail projects

9 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 109 Methodologies Employed NCHRP 350 B/C evaluation sometimes used

10 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 110 Standards Roadside Design Guide NCHRP 350 Some states develop own policies Judgment and expertise

11 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 111 Factors for Upgrade Other Factors: Upgrade with scheduled projects Accident history Presence of a 3R/4R project Compliance with 350 New standards FHWA mandates Physical Characteristics: Obsolescence Height Lack of blockouts Substandard end treatment Insufficient length of need Rail condition Crashworthiness

12 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 112 Survey Work to be Done Continue compiling responses Perform necessary follow-up on responses Incorporate survey responses within working paper on previous work

13 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 113 Evolving Guardrail Standards and Resource Allocation

14 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 114 Old versus new Run of rail versus end treatment No installation versus new Repair versus replacement Costs –Upgrade: Removal and replacement –New: Installation costs –Disposal and Recycling –Lifecycle Costs Motivation - How Standards Affect Resource Allocation

15 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 115 Objectives Gain understanding for characteristics of multiple guardrail systems Grasp weaknesses in current response to evolving standards Put strengths together for a state-of-the-art model for resource allocation

16 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 116 Mathematical Models and Resource Allocation Review and evaluate models to aid in decision-making processes Develop state-of-the-art decision tool

17 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 117 Mathematical Models and Resource Allocation Devise Review (Mesterton-Gibbons, 1995);(Nicholson, 1989); (Hillier- Lieberman, 1995) FHWA Videos (Trinitron and Syro) AASHTO

18 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 118 International Comparison of Guardrail Standards Switzerland Japan France

19 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 119 No barriers should be shorter than 50 meters Barriers where ADT >= 10,000 or where average speeds are > 75 km/h Switzerland

20 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 120 Switzerland On any roads where: Retaining walls and bridges, if height exceeds 2 meters Parallel with railways, or watercourses deeper than 1 meter Large obstacles must be protected 50 – 60 meters before the obstacle

21 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 121 Trees closer than 10 meters to the road are removed whenever possible On national divided highways the federal administration requires the installation of median barriers without regard to traffic volume Switzerland

22 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 122 On divided highways –Along the median –Along fills with heights exceeding 4 meters and slopes steeper than 1.5:1 Switzerland

23 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 123 Switzerland On roads with less than 10000 vehicles ADT barriers should only be installed in cases where the conditions are aggravated by complications such as, Along curves, if the radius of a curve is smaller than the prescribed minimum for the design speed If the roadway is often covered with sleet

24 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 124 Japan A study by the Japanese Public Works Research Institute seeks to evaluate the effect on accidents of crash barriers from a strictly economic standpoint, using the formula: B = (N b * D b ) – (N a * D a ) – M – I

25 Center for Risk Management of Engineering Systems University of Virginia, Charlottesville 125 Japan Where B = benefit from guardrail construction N b = number of run-off accidents expected before guardrail installation D b = expected damage in a run-off accident before guardrail installation N a = number of collision accidents expected after guardrail installation


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