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

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RISK-BASED MANAGEMENT OF GUARDRAILS: SITE SELECTION

AND UPGRADINGPresented to

Project Steering Committeeby

The Center for Risk Management of Engineering Systems

February 23, 2000

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

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Agenda

• Introduction• Data driven approach to risk assessment• Data representation for site screening• Multiple objectives in the selection among

candidate projects• Discussion

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

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Project TeamCenter for Risk Management of Engineering Systems

James H. Lambert, Research Assistant Professor of Systems EngineeringYacov Y. Haimes, Quarles Professor of Systems Engineering and Civil Engineering and

Center DirectorJeffrey A. Baker, BS/MS Student

Capstone TeamChristian Baldwin

Irene JacoubMike Raker

VDOT Richmond DistrictTravis Bridewell, District Traffic Engineer, Richmond District

Jeff Wilkinson, Transportation Engineer, Traffic Engineering Section, Richmond DistrictBaron Gissendaner

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

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Project Team (cont.)Virginia Transportation Research Council

Wayne S. Ferguson, Research Manager Steering Committee

Steve Edwards, Transportation Engineer Senior, Traffic Engineering Division, Central OfficePaul Kelley, Transportation Engineer, Location and Design Division, Central Office

Charlie Kilpatrick, Fredericksburg Resident Engineer, Fredericksburg DistrictBob McCarty, Senior Field Operations Engineer, Federal Highway Administration - Richmond

Ginger Quinn, District Safety Officer, Traffic Engineering Section, Salem DistrictNancy Berry, Transportation Engineering Program Supervisor, Location and Design Division,

Central Office

Additional Current and Former Resident EngineersBill BushmanAngela TuckerWillie Gentry

Alan Leatherwood

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

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Problem Statement

• Public and transportation-agency values concerning the location of roadway guardrails are in need of clarification

• The concerns of Virginians for adequate guardrails are high relative to the national norms

• Current practice in some VDOT Districts for selecting locations for new guardrails is based on citizen complaints, a general knowledge of roadway needs from local engineers, and accident history

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

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Problem Statement (cont.)

• Kentucky has developed a hazard-index point system (Kentucky Transportation Center Report KTC-89-39 "Warrants and Guidelines for Installation of Guardrail")

• There are hundreds of candidate locations on the thirteen-county secondary system of Richmond District

• Particular locations in New Kent and Charles City County have been the focus of a related preliminary study in Richmond District

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

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Purpose and Scope

The effort will adopt quantitative and qualitative factors/endpoints and develop associated cost-

benefit-risk tradeoff methodology to support the preliminary screening and subsequent evaluation of guardrail site selection and upgrading with limited

available funding

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

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Purpose and Scope (cont.)

• Four associated objectives:– Review and evaluation of what others have done– Adoption of assessment methods and quantitative and

qualitative factors/endpoints– Development of a tradeoff methodology– Specification and prototype development of databases

• Acknowledge that guardrails sometimes increase danger to vehicles

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

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A Data Driven Approach to Risk Assessment and Safety Evaluation of

Guardrail

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

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MotivationA data driven approach to assessing risk and

evaluating safety of candidate guardrail locations by determining data uses for screening and

evaluation phases, identifying data needs,and evaluating data collection methods.

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

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Screening

G u a rd ra ilC o vera ge

A cc id e n tH is to ry

C o m p la in tR e c o rd

A D T

P o ss ib le S ea rch es

• Select corridors to examine

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

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Evaluation• Select locations along given corridor

C o s t H a za rd ch a ra cte ris ticsse verity, le n g th

R o a d ch a ra c te ris t icssh o u ld e r w id th ,s lo pe , cu rva tu re

P o ss ib le s ea rch es

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

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Data Needs• Screening

– Guardrail inventory• % unprotected hazards• % guardrail coverage• % substandard guardrail

– Accident history• FO accidents per DVMT• Fatalities caused by FO accidents

– ADT– Complaint record

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

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Data Needs (cont.)• Evaluation

– Cost (installation, upgrade)– Length of hazard– Severity of hazard– Shoulder width– Slope– Curvature

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

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Accident Statistics• Disadvantages

– Unreported accidents– Severity iceberg– First and most harmful event – Fatalities do not occur frequently enough to

be statistically predictive– Random nature of road accidents

(Adams, 1996), (Michie and Bronsted, 1994)

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

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Accident Statistics (cont.)• Advantages

– Available and assessable– Factual– Public interest

(Adams, 1996), (Michie and Bronsted, 1994)

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

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New Kent Case Study• Initial Data Collection

– Routes 609-622• Corridor Analysis

– Corridors for which guardrail inventory is available

– Routes 33, 106, 249, 273

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

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Corridor Analysis• Compare routes for frequency and severity of

accidents• Select routes that have greatest accidents/miles• Compare results with current guardrail

inventory• Advantages

– Reduce random chance associated with accidents– Use summary statistics available in HTRIS

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

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Corridor Analysis (cont.)• Disadvantages

– Overlooks role of hazardous locations– Many locations of mediocre severity vs. one

location of very high severity

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

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Corridor Screening

33 1.09 0 0 2 2 0 4 $21,000 4 4 0 0 0106 5.08 9194 1 16 16 1 24 $151,990 33 14 192 140 5.845249 4.78 18805 0 41 51 0 72 $3,825,090 92 19 262 205 0273 4.48 17050 1 19 12 1 29 $121,540 32 22 100 91 3.152

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

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Corridor Screening (cont.)

0

0.001

0.002

0.003

0.004

0.005

Accidents per

DVMT

33 106 249 273

Corridor

Total vs. Fixed Object Accidents per DVMT

All Accidents

Fixed Object Accidents

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

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Objective

Develop a graphical tool for a guardrail and hazard inventory system for resource

allocation and decision making

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

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Access to the New Kent Guardrail Data

• Graphically represent what resident engineers know using an electronic map indicating the locations of:– Guardrails– Obstacles– Accidents– Complaints, etc.

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

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Electronic Map• Layered spatial data, creating different

views– Regional view– Zone view– Corridor view– Site view

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

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Regional View