HSM Implementation ToolsSafety AnalystKim Kolody Silverman, PECH2M HILL representing

Illinois Department of Transportation

We commonly trade safety off against something else

Safety Right-of-Way

Costs

Environment

We’re Interested in Other Impacts for Project Level Decisions – What About Substantive Safety?

Safety Environmental Traffic Right-of-Way Costs Impacts Impacts Operations

• Traffic Noise Model 1.0

• CAL3QHC• Mobile 5a• 3-D Visualization• CITYGREEN

• HCM• CORSIM• PASSER• TRANSYT7F• VISSIM

• Construction Plans• Cost Models• Real estate appraisals• DOT databases

Design Criteria (nominal

safety)

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HSM Tools

3

Part AIntroduction

Human Factors Fundamental

s

Part D Crash

Modification Factors (CMFs)

Part B

Roadway Safety Management

Process

Part CPredicti

ve Method

Tools for Implementing HSMExcel SpreadsheetsInteractive Highway Safety Design

Model (IHSDM)Safety Analyst

HSM Excel Spreadsheets

Project level basisSimple,

straightforwardLimited data

requiredWorksheet 3A -- Predicted and Observed Crashes by Severity and Site Type Using the Site-Specific EB Method

(1) (2) (3) (4) (5) (6) (7) (8)Site type

Predicted average crash frequency (crashes/year)

Observed crashes,

Nobserved (crashes/year)

Overdispersion Parameter, k

Weighted adjustment, w

Expected average crash

frequency, Nexpected

N predicted (TOTAL)

N predicted (FI)

N predicted (PDO)

Equation A-5 from Part C Appendix

Equation A-4 from Part C Appendix

ROADWAY SEGMENTS

Segment 1 6.106 1.960 4.146 10 0.157 0.510 8.0

Segment 2 0.495 0.159 0.336 2 2.360 0.461 1.3

Segment 3           1.000 0.0

INTERSECTIONS

Intersection 1 2.847 1.181 1.665 3 0.540 0.394 2.9Intersection 2

          1.000 0.0

Intersection 3   

      1.000 0.0

COMBINED (sum of column) 9.448 3.300 6.147 15 -- -- 12.3

Interactive Highway Safety Design Model

Provides expected safety, operational performance

HSM techniques +Modules to compare

design to standardsRequires detailed data

inputFree

The Vision of SafetyAnalyst – Software Akin to the HCS+

Definitive; represents

quantitative ‘state-of-the-art’

information

Widely accepted within professional

practice of transportation engineering

Science-based; updated regularly to

reflect research

1

2

3

Purpose of SafetyAnalyst

SafetyAnalyst provides state-of-the-art tools for safety management that provide capabilities beyond those currently available to highway agencies

Effectiveness of decision makingEfficiency of decision support

Intended for those who will:Identify candidate sites for safety

improvementsInvestigate the types of safety

improvements needed for specific sitesAssess whether specific safety

improvements are economically justified and should be programmed

Evaluate the safety effectiveness of implemented projects

Road Safety Management Process

Network Screening

Diagnosis & Countermeasure Selection

Economic Appraisal & Prioritization

Safety Effectiveness Evaluation

Network Screening

Review highway network (or any portion of the network) to identify sites with potential for safety improvement

Identify sites that are candidates for further investigation

6 different methods for screening

Module 1Network Screening

Helps to identify accident patterns of interest at specific sites

Guides user in the diagnosis of safety problems at specific sites

Suggests countermeasures that address identified accident patterns of interest

Lets user select appropriate countermeasures

Module 2 Diagnosis & Countermeasure Selection

Perform economic analysis of alternative countermeasures for a specific site

Perform economic analysis of countermeasures across selected sites

Select mix of sites and countermeasures to maximize benefits within a given budget

Develop priority ranking of alternative improvements

Module 3Economic Appraisal & Prioritization

Conduct before-after evaluations of implemented countermeasures

Quantify the safety effectiveness of implemented countermeasures based on:Percent change in accident frequencyChange in proportion of target

accidents

Module 4 – Countermeasure Evaluation

Safety Effectiveness Evaluation

Test Data Input for IllinoisCategoryTest Areas 3 Counties

1 TownshipRoute Type State and Local

facilitiesNumber of roadway segments

28,093

Roadway mileage 7,471Number of intersections 18,704Number of crashes 118,093Note: Counties are Champaign, Sagamon, Vermillion and the township is West ChicagoCrashes represent 2005 to 2009 fatal, A-injury, B-injury, C-Injury, and PDO

Data Process for Illinois

3.5 hours for data import15 minutes for crash data

script2.5 hours for post processing

15 minutes for calibration

Total = 6.5 hours for approximately 5% of total data

set

Challenges

Data input and processing takes some time

Requires user trainingRequires agency supportCost

Challenges

Data Input and ProcessingCoordinate multiple data sources, data

ownersDetermining business rules Complete data where not availableData input (SQL vs Oracle)Data set-up process timeNetwork screening process time

Powerful analysis toolAutomates HSM proceduresCalibrates national default SPFsScreen large amounts of dataProvides consistent evaluation and

results for decision making

Benefits

Flexible for userCountermeasures, service life, costs

includedAutomates various economic

comparisonsSet of tools that allows for a better

selection of sites and improved prioritization techniques for decision making to maximize resources to reduce severe crashes

Benefits

Forces coordination between divisions of the agencyBetter dataMore dataUnderstanding of data application

across the agency which may influence potential changes in agency business practices

Benefits

HSM Implementation Tool: Recommendations

Use HSM Excel Spreadsheets where appropriate

Apply IHSDM where appropriate

Start preparing Safety Analyst for use

Determine funding options

Start the process of data identification, mapping

Start educating staff at central office

Engage IT staff

HSM Implementation Tool: Safety Analyst Recommendations

Start with a small test data set

Good team coordination

Decision making in data set-up

Seek assistance from AASHTO, peers

HSM Implementation Tool: Safety Analyst Recommendations

For more informationHighway Safety Manual

http://www.highwaysafetymanual.org/

Safety Analyst http://www.safetyanalyst.org/

Interactive Highway Safety Design Modelhttp://www.tfhrc.gov/safety/ihsdm/ihsdm.htm

Questions

Kim Kolody, PECH2M HILL

(773) 458.2883Kim.Kolody@ch2m.comkolodyka@illinois.gov

Priscilla Tobias, PEState Safety EngineerIllinois Department of

Transportation(217) 782-3568

priscilla.tobias@illinois.gov