center for risk management of engineering systems university of virginia, charlottesville 1...

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

The Project Steering Committee

by

The Center for Risk Management of Engineering Systems

September 15th, 2000


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Project TeamVDOT Richmond District

Travis Bridewell, District Traffic Engineer, Richmond DistrictJeff Wilkinson, Transportation Engineer, Traffic Engineering Section, Richmond District

Baron Gissendaner

Virginia Transportation Research CouncilWayne S. Ferguson, Research Manager

Steering CommitteeSteve Edwards, Transportation Engineer Senior, Traffic Engineering Division, Central Office

Paul Kelley, Transportation Engineer, Location and Design Division, Central OfficeCharlie Kilpatrick, Fredericksburg Resident Engineer, Fredericksburg District

Bob McCarty, Senior Field Operations Engineer, Federal Highway Administration - RichmondGinger Quinn, District Safety Officer, Traffic Engineering Section, Salem District

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


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Project Team (cont.)Additional Current and Former Resident Engineers

Bill BushmanAngela TuckerWillie Gentry

Alan LeatherwoodDan Roosevelt

Center for Risk Management of Engineering SystemsJames 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 StudentKenneth Peterson, Undergraduate Student

Capstone TeamChristian Baldwin

Irene JacoubMike Raker


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Agenda

I. Motivation

II. Data representation for Hazard Catalog

III. Data representation for Corridor Screening

IV. Data representation for Site Prioritization

V. Discussion


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I. Motivation


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Motivation

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

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

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


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Motivation (cont.)

• E.g., there are hundreds of candidate locations on the thirteen-county secondary system of Richmond District; over 50,000 miles of roadway in Virginia

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

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


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Purpose and Scope• Objectives:

– Review and evaluation of what others have done

– Adoption of assessment methods and quantitative and qualitative factors

– Development of a tradeoff methodology– Specification and prototype development of

databases


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Overview of ApproachA data driven approach to assessing risk andevaluating safety of candidate guardrail locations by

• Catalog • Screening phases• Evaluation phases• Data needs in a case study• Developing Software


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Corridor Screening

G u a rd ra ilC o vera ge

A cc id e n tH is to ry

A D T C o m pla in tR e co rd

A ttribu te s C o n sid e red

• Select corridors to examine


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Site Prioritization

• Select locations along given corridor

Existing G uardra ils H azard characteristicsseverity, length, s lop e

R oad characteristicsshoulder w idth,

curvature, speed lim it, AD T

C ost o f insta lla tion or upgrade

Possib le searches


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New Kent Case Study

• Data Collection for Corridor Screening Tool– Accident statistics of given corridors – Routes 601-665

• Data Collection for Site Prioritization and Hazard Catalog Tool– Routes 611, 613, 640, 665


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II. Hazard Catalog Tool


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Purpose

• Compile an inventory of hazard sites and guardrail coverage, and conditions of guardrails

• Compare and contrast routes to determine which are in need of further study

• Present in a graphical format information pertinent to decisions about improvements


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Severity Guidelines


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Hazard Catalog Screening

to 07/27/00

Incl

ud

e (Y

or

N)?

ID N

um

be

r

Da

te M

od

ifie

d

Nu

mb

er

of L

an

es

Flo

w D

ire

ctio

n

Rig

ht o

r L

eft

Re

lativ

e to

:

Be

gin

nin

g M

ilep

ost

(m

iles)

En

d M

ilep

ost

(m

iles)

Le

ng

th o

f Ha

zard

(fe

et)

Exi

stin

g R

un

-on

Typ

e

Exi

stin

g M

ain

Ru

n T

ype

Exi

stin

g R

un

-Off

Typ

e

Exi

stin

g O

the

r T

ype

Va

lue

of E

xist

ing

Se

ctio

n

Pro

po

sed

Ru

n-o

n

Pro

po

sed

Ma

in R

un

Pro

po

sed

Ru

n-O

ff

Pro

po

sed

Oth

er

Re

mo

val C

ost

Pe

r F

oo

t

To

tal C

ost

for

Pro

po

sed

Im

pro

vem

en

t

Se

veri

ty In

de

x

Gu

ard

rail

Str

ike

s

AD

T (

Ve

hic

les

pe

r D

ay)

Ha

zard

DV

MT

(D

aily

Ve

hic

le

Mile

s T

rave

led

)

Nu

mb

er

of R

ela

ted

Acc

ide

nts

Se

veri

ty o

f Co

mp

lain

ts

Y 1 07/00 2 N R E611 1.565 1.603 201 $0 4 5 6 7 $6,207 4 258 9.8

Y 2 07/00 2 N R E611 1.400 1.460 317 1 2 3 $3,584 4 5 6 7 $7,485 9 258 15.5

Y 3 07/00 2 N R E611 0.437 0.475 201 $0 4 5 6 7 $6,207 8 782 29.7

To Guardrail Types To Workbook Summary Table

To Route Summary Table

To Next Route

Comments

Near Railroad, Steep Embankment

Sub GR w /Blunts

Water Hazard

01/01/00

Accident Data Covers Dates:Route=

Length of Route=

County/City=

613

Unknown

NK

Location Existing Proposed


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Hazard Catalog Screening (cont.)

Size of bubbles represent cost/value

Existing Guardrails vs. Proposed Installations at Unprotected Sites

0

2

4

6

8

10

0 5 10 15 20 25 30 35

Daily Vehicle Miles Traveled

Sev

erit

y

Costs of Proposed Guardrails Values of Existing Guardrails


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Size of bubbles represent cost

Cost Functions of Prosposed Sites on Different Routes

-5

0

5

10

15

20

25

0 20 40 60 80 100 120 140


Su

mm

atio

n S

ever

ity

613

611

665

640

6xx

6xx

6xx

6xx


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Size of bubbles represent cost/value

Existing Guardrail Costs vs. Proposed Installations at Unprotected Sites

613

613613

611611

611

611

665640

640

0

2

4

6

8

10

0 50 100 150 200 250 300 350 400 450


Sev

erit

y

Value of Existing Guardrails Cost of Proposed Guardrails


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IV. Corridor Tool


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Purpose

• Compare corridors for frequency and severity of accidents

• Highlight corridors that have greatest accidents/DVMT ratio

• Compare results with current guardrail coverage


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Corridor ScreeningInput Worksheet

Include (Y or N)?

Corridor Referenced toBeginning Milepost

End Milepost

Length in Miles

ADT DVMTNumber of

Related Accidents

Number of Related Injuries

Number of Related Fatalities

Amount of Related Property Damage

Y 601 N/A 0.00 2.58 2.58 253 653 1 1 0 $11,200

Y 606 N/A 0.00 7.40 7.40 761 5631 4 3 0 $11,000

Y 608 N/A 0.00 7.24 7.24 263 1904 3 1 0 $9,500

Y 609 N/A 0.00 3.96 3.96 786 3113 1 0 0 $12,000

Y 610 N/A 0.00 3.01 3.01 231 695 2 4 0 $7,000

Y 611 N/A 0.00 5.29 5.29 733 3878 3 3 1 $8,500

Y 613 N/A 0.00 3.76 3.76 782 2940 1 1 0 $10,000

Y 621 N/A 0.00 1.20 1.20 232 278 1 0 0 $1,200

Y 623 N/A 0.00 7.40 7.40 137 1014 1 1 0 $3,200

Y 627 N/A 0.00 10.44 10.44 952 9939 3 3 0 $3,100

Y 628 N/A 0.00 6.78 6.78 282 1912 1 2 1 $833

Y 629 N/A 0.00 3.78 3.78 959 3625 1 0 0 $3,500

Y 632 N/A 0.00 6.94 6.94 552 3831 1 3 0 $3,500

Y 634 N/A 0.00 5.30 5.30 92 488 1 1 0 $5,000

Y 638 N/A 0.00 4.30 4.30 481 2068 2 0 0 $9,000

Y 640 N/A 0.00 5.07 5.07 1028 5212 6 6 0 $22,850

Y 658 N/A 0.00 0.50 0.50 87 44 1 1 0 $3,000

Y 665 N/A 0.00 2.90 2.90 1118 3242 2 0 0 $10,500

Corridor Comparison Tool Input Area

Yellow Filled Cells Indicate User Input Areas


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Corridor Screening (cont.)


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IV. Site Prioritization Tool


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Purpose

• Decide which sites should be improved with the current budget constraint

• Consider multiple criteria


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Objective (cont.)

1

108

2

37

9

4

5

6

1

108

2

37

9

4

5

6

1

108

2

37

9

4

5

6

1

108

2

37

9

4

5

6


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Objectives of Guardrail Selection

M ile s o f R o a d P ro te c ted

S e verity P ro tec ted

V e h ic le -M ile s P ro te c ted

S e ve rity-M ile s P ro te c ted

S e ve rity-V e h ic le -M ile s P ro te c ted

M a x im ize

C o s t

M in im ize


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Example

• Maximize length of hazard protected

• Subject to budget constraints– (E.g. total cost < $30,000)


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Site Prioritization Tool Analysis

• Compare sites and their characteristics (cost, severity, ADT)

• Select routes with the highest benefit/cost ratios that fall within a budget constraint


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Site Prioritization


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Site Prioritization

(cont.)

Leng

th (

ft)/

Cos

t ($

) R

atio

Loca

tion

Cos

t ($

)

Cum

ulat

ive

Cos

t ($

)

Sev

erity

/Cos

t($)

R

atio

Loca

tion

Cos

t ($

)

Cum

ulat

ive

Cos

t ($

)

0.08821 8 $19,284 $19,284 0.00133 3 $6,000 $6,0000.08809 10 $19,185 $38,469 0.00133 9 $6,000 $12,0000.059 6 $8,475 $46,944 0.0013 2 $6,900 $18,900

0.0471 2 $6,900 $53,844 0.00096 7 $6,225 $25,1250.04286 5 $7,000 $60,844 0.00067 1 $6,000 $31,1250.04016 7 $6,225 $67,069 0.00052 10 $19,185 $50,3100.03333 1 $6,000 $73,069 0.00047 8 $19,284 $69,5940.03333 4 $6,000 $79,069 0.00035 6 $8,475 $78,0690.025 3 $6,000 $85,069 0.00029 5 $7,000 $85,0690.01 9 $6,000 $91,069 0.00017 4 $6,000 $91,069N/A 11 N/A $91,069 N/A 11 N/A $91,069N/A 12 N/A $91,069 N/A 12 N/A $91,069N/A 13 N/A $91,069 N/A 13 N/A $91,069N/A 14 N/A $91,069 N/A 14 N/A $91,069N/A 15 N/A $91,069 N/A 15 N/A $91,069N/A 16 N/A $91,069 N/A 16 N/A $91,069N/A 17 N/A $91,069 N/A 17 N/A $91,069N/A 18 N/A $91,069 N/A 18 N/A $91,069N/A 19 N/A $91,069 N/A 19 N/A $91,069N/A 20 N/A $91,069 N/A 20 N/A $91,069N/A 21 N/A $91,069 N/A 21 N/A $91,069N/A 22 N/A $91,069 N/A 22 N/A $91,069N/A 23 N/A $91,069 N/A 23 N/A $91,069N/A 24 N/A $91,069 N/A 24 N/A $91,069N/A 25 N/A $91,069 N/A 25 N/A $91,069

P rotected Severity P rioritizationP rotected M iles P rioritization


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Site Prioritization

(cont.)

Solution Comparison

Budget: $50,000

Length of Hazard

Protected (ft)

Severity Protected

Average Daily Traffic

(Vehicles per day)

Vehicle-Miles

Protected

Severity-Miles

Protected

Severity-Vehicle-Miles

Protected

Solution 1 3891 22 576.0621212 174.8 6.384 1601.3Solution 2 985 35 83.53787879 3.2 1.308 23.0Solution 3 3891 22 576.0621212 174.8 6.384 1601.3Solution 4 3716 28 546.0147727 171.4 6.654 1597.1Solution 5 3541 27 552.35 171.1 6.327 1593.4

Total Possible: 5376 60 6005 705.5 7.844 5751.6

Percentage of Possible

Hazard Length

Protected

Percentage of Possible Severity

Protected


Average Daily Traffic

(Vehicles per day)


Vehicle-Miles

Protected


Severity-Miles

Protected

Percentage of Possible Severity-

Vehicle-Miles Protected

Solution 1 72.4% 36.7% 9.6% 24.8% 81.4% 27.8%Solution 2 18.3% 58.3% 1.4% 0.5% 16.7% 0.4%Solution 3 72.4% 36.7% 9.6% 24.8% 81.4% 27.8%Solution 4 69.1% 46.7% 9.1% 24.3% 84.8% 27.8%Solution 5 65.9% 45.0% 9.2% 24.2% 80.7% 27.7%

Bubble Charts for the Solutions follow this page. Please refer to the tabs at the bottom of the screen.

Prioritize All


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Site Prioritization (cont.)

Size of bubbles represent cost/value ($)


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Comparison of Results

• Results can be compared to show the consistency of need at a location

• Budget constraint kept constant

• Example:– Locations 1,2,3,7, and 9 are recommended by

the model to maximize severity protected


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Summary and Future Work

• The spreadsheet tools provides a way to optimally select hazard sites within the budget constraints

• Comparing results from different solutions can reveal the locations most appropriate for improvement


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Summary and Future Work (cont.)

• Issues for Implementation– Definition of Severity– Environmental Factors– Curvature of Road


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Web Page

• http://www.virginia.edu/~risk/guardrail/• Public reference for guardrails and treatment of

issue• Communication between VDOT and Capstone• Software, instructions, and powerpoint


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The Web Site

• Statement of Work• Guardrail Photos• Current Team• Contact Information• Related Links• Downloads


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Discussion

center for risk management of engineering systems university of virginia, charlottesville 1...

Documents

civil engineering

traffic engineering

traffic engineering

district traffic engineer

virginia kentucky

motivation slide

transportation engineer

center director jeffrey