RISK-BASED MANAGEMENT OF GUARDRAILS: SITE SELECTION AND UPGRADING

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RISK-BASED MANAGEMENT OF GUARDRAILS SITE
SELECTION AND UPGRADING

• Presented to
• Project Steering Committee
• by
• The Center for Risk Management of Engineering
  Systems
• February 9, 2000

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Agenda

• Overview of risk assessment/management
• Review of proposal and Comparison Tool
• Literature review and survey
• Risk assessment for guardrails
• Corridor analysis for screening
• Integration of electronic map and catalog
• Budget optimization for evaluation
• Webpage
• Discussion

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Overview of the Risk Assessment and Management
Process
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Technological Age
Risk Management ? Optimal Balance
Uncertain Benefits
Uncertain Costs

• Technology Management
• Man/Machine/Software Systems
• Planning
• Design
• Operation

Risk Management
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Risk assessment and management must be an
integral part of the decisionmaking process
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RISKA Measure of the Probability and Severity
of Adverse Effects
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RISK VS. SAFETYMeasuring risk is an empirical,
quantitative, scientific activity (e.g.,
measuring the probability and severity of
harm).Judging safety is judging the
acceptability of risks -- a normative,
qualitative, political activity. (After
William W. Lowrance, 1976)
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RISK ASSESSMENT AND MANAGEMENT

• What can go wrong?
• What is the likelihood that it will go wrong?
• What are the consequences?
• What can be done?
• What options are available and what are their
  associated trade-offs in terms of all costs,
  benefits, and risks?
• What are the impacts of current management
  decisions on future options?

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Review of Goals/Tasks/Schedule
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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

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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

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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

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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

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Methods
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(1) Review of Literature

• Review and evaluation of past studies, theory and
  methodology, and databases
• Build on past surveys
• Sample of resources
• Bryden, J.E. and J.S. Fortuniewicz. Traffic
  Barrier Performance Related to Vehicle Size and
  Type. Transportation Research Record 1065, TRB,
  National Research Council, Washington D.C., 1986.
• Calcote, L.R. Cost-Effectiveness Model for
  Guardrail Selection. Transportation Research
  Record, 679, TRB, National Academy of Sciences
  1978, pp. 8-12.
• Calcote, L.R. Strategy for Selection and
  Placement of Highway Guardrails. Transportation
  Research Record 736, TRB, National Academy of
  Sciences, 1979.
• Kentucky Transportation Center, Report KTC-89-39
  "Warrants and Guidelines for Installation of
  Guardrail", 1989.
• Mak, King K. Cost-Effectiveness Evaluation of
  Roadside Safety Improvement. Transportation
  Research Circular 416, TRB, National Research
  Council, 1993.
• Michie, Jarvis D. and Bronstad, Maurice E.
  Highway Guardrails Safety Feature or Roadside
  Hazard? Transportation Research Record 1468,
  TRB, National Research Council, 1994.
• Pigman, Jerry G. and Agent, Kenneth R.
  Guidelines for Installation of Guardrail.
  Transportation Research Record 1302, TRB,
  National Research Council, 1991.
• Stewart, Douglass. Pedestrian Guardrails and
  Accidents. Traffic Engineering and Control,
  September 1988, pp.450-455.
• Tarko, Andrzej P., Sinha, Kumares C., Farooq,
  Omer. Methodology for Identifying Highway Safety
  Problem Areas. Transportation Research Record
  1542, TRB, National Research Council. 1196.

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(2) Formation of Steering Committee and
Communication with Resident Engineers

• A project steering committee has been formed to
  guide the effort
• A sample of resident engineers representative of
  diverse VDOT districts will support
• Identification of appropriate assessment
  factors/endpoints
• Refining the desired features of the developing
  methodology

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(3) Adoption of Quantitative and Qualitative
Factors/Endpoints

• Adopt models for the assessment of
  factors/endpoints from data and engineering
  judgment
• Where quantitative models are unavailable,
  qualitative scales will be defined, i.e.,
  highest to lowest levels for a given
  attribute
• Ensure that an encompassing set of quantitative
  and qualitative factors/endpoints can be
  considered and balanced

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(4) Characterization of Options

• The effort will distinguish options in two
  phases
• (1) Preliminary screening of candidate sites
• (2) Evaluation of the smaller set of screened
  sites based on more detailed analysis
• The developing methodology will accommodate and
  distinguish different levels of the data
  available for assessment at the two phases

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(5) Tradeoff Analysis for Guardrail Management

• Develop methodology for addressing the tradeoffs
  among costs, risks, and other factors/endpoints
• Develop an automated spreadsheet that facilitates
  the calculations and tradeoff comparison

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(5) Tradeoff Analysis for Guardrail Management

• Graphical interfaces previously designed are only
  examples of the direction proposed in the current
  effort because of shortcomings in their
  application to guardrail management
• Inability to appreciate the merits of a large
  number of projects
• Complexity of interpretation and evaluation of
  imprecisely known quantities
• Tacit encouragement to ignore yet unquantified
  factors

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Intersection Design Evaluation
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(6) Databases and Demonstrations

• Perform a case study with a sample of locations
  in the Richmond District
• Specify and apply databases necessary to quantify
  the factors/endpoints
• Interfaces of the developing software and VDOTs
  electronic databases will be addressed through
  internet hyperlinks and automated access
• The effort will specify data requirements that
  are appropriate to the capabilities of the
  residencies

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(7) Reports, Presentations, and Workshop

• Complete progress and final reports,
  presentations, and a training workshop for
  example the Resident Engineers group and the
  District Traffic Engineers group
• Conform to the publication requirements of the
  Virginia Transportation Research Council
• Provide documentation and spreadsheets via a
  prototype internet web site at the University of
  Virginia

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Expected Benefits

• Knowledge of what others have done
• Characterization of VDOT engineers experience
  with guardrail management
• Improved understanding of the balance among
  costs, average and catastrophic risk reduction,
  and other factors in the site selection and
  upgrading of guardrails

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Expected Benefits (cont.)

• Informed, effective, and systematic allocation of
  limited funds for guardrails
• Databases of parameters related to guardrail
  performance, a basis for future research
• Education of VDOT professionals in the state of
  the art of cost-benefit-risk tradeoff analysis