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 23, 2000. Agenda. Introduction Data driven approach to risk assessment Data representation for site screening

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Presentation Transcript

Risk based management of guardrails site selection and upgrading


Presented to

Project Steering Committee


The Center for Risk Management of Engineering Systems

February 23, 2000



  • Introduction

  • Data driven approach to risk assessment

  • Data representation for site screening

  • Multiple objectives in the selection among candidate projects

  • Discussion

Project team

Project Team

Center for Risk Management of Engineering Systems

James H. Lambert, Research Assistant Professor of Systems Engineering

Yacov Y. Haimes, Quarles Professor of Systems Engineering and Civil Engineering and Center Director

Jeffrey A. Baker, BS/MS Student

Capstone Team

Christian Baldwin

Irene Jacoub

Mike Raker

VDOT Richmond District

Travis Bridewell, District Traffic Engineer, Richmond District

Jeff Wilkinson, Transportation Engineer, Traffic Engineering Section, Richmond District

Baron Gissendaner

Project team cont

Project Team (cont.)

Virginia Transportation Research Council

Wayne S. Ferguson, Research Manager

Steering Committee

Steve Edwards, Transportation Engineer Senior, Traffic Engineering Division, Central Office

Paul Kelley, Transportation Engineer, Location and Design Division, Central Office

Charlie Kilpatrick, Fredericksburg Resident Engineer, Fredericksburg District

Bob McCarty, Senior Field Operations Engineer, Federal Highway Administration - Richmond

Ginger Quinn, District Safety Officer, Traffic Engineering Section, Salem District

Nancy Berry, Transportation Engineering Program Supervisor, Location and Design Division, Central Office

Additional Current and Former Resident Engineers

Bill Bushman

Angela Tucker

Willie Gentry

Alan Leatherwood

Problem statement

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

Problem statement cont

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

Purpose and scope

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

Purpose and scope cont

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

A data driven approach to risk assessment and safety evaluation of guardrail

A Data Driven Approach to Risk Assessment and Safety Evaluation of Guardrail



A 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.



  • Select corridors to examine



  • Select locations along given corridor

Data needs

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

Data needs cont

Data Needs (cont.)

  • Evaluation

    • Cost (installation, upgrade)

    • Length of hazard

    • Severity of hazard

    • Shoulder width

    • Slope

    • Curvature

Accident statistics

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)

Accident statistics cont

Accident Statistics (cont.)

  • Advantages

    • Available and assessable

    • Factual

    • Public interest

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

New kent case study

New Kent Case Study

  • Initial Data Collection

    • Routes 609-622

  • Corridor Analysis

    • Corridors for which guardrail inventory is available

    • Routes 33, 106, 249, 273

Corridor analysis

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

Corridor analysis cont

Corridor Analysis (cont.)

  • Disadvantages

    • Overlooks role of hazardous locations

    • Many locations of mediocre severity vs. one location of very high severity

Corridor screening

Corridor Screening

Corridor screening cont

Corridor Screening (cont.)



Develop a graphical tool for a guardrail and hazard inventory system for resource allocation and decision making

Access to the new kent guardrail data

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.

Electronic map

Electronic Map

  • Layered spatial data, creating different views

    • Regional view

    • Zone view

    • Corridor view

    • Site view

Regional view

Regional View

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