hsm use and training karen k. dixon, ph.d., p.e. oregon state university

HSM Use and Training

Karen K. Dixon, Ph.D., P.E.Oregon State University

Presentation Summary

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I. WHAT IS THE HSM?Overview of the new HSM

What is the HSM?

The Vision of the HSM - A Document Akin To the HCM

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WHAT THE HSM IS NOT

• The HSM does not set requirements or mandates• The HSM is not a best practice document for design or

operations.• The HSM contains no warrants or standards

and does not supersede other publications that do.

vs

The HSM does not establish a legal

standard of care nor does it create a duty

to the public.

II. WHY DO WE NEED THE HSM?

Overview of the new HSM

Is This Road “Safe” or “Unsafe”?

What does safety really mean?

Examined in reference to compliance with standards, warrants, guidelines and sanctioned design procedures

The expected or actual crash frequency and

severity for a highway or roadway

Highway Safety Has Two Dimensions

*Ezra Hauer, ITE Traffic Safety Toolbox Introduction, 1999

CR

AS

H R

ISK

DESIGN DIMENSIONLane Width, Radius of Curve, Stopping Sight Distance, etc.

CR

AS

H R

ISK


Unlike Nominal Safety, Substantive Safety is a

Continuum

Substantive Safety Nominal Safety

Nominal Safety versus Substantive Safety

CR

AS

H R

ISK


Low NominalLow

Substantive

Low NominalLow

Substantive

Low NominalHigh

Substantive

Low NominalHigh

Substantive

High NominalLow

Substantive

High NominalLow

Substantive

High NominalHigh

Substantive

High NominalHigh

Substantive

Substantive Safety May Vary When Nominal Safety Does Not

Existing ConditionsExisting Conditions Alternative 1Alternative 1

Alternative 2Alternative 2 Alternative 3Alternative 3

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)

Mor

e qu

antit

ativ

e

Gre

ater

wei

ght

The HSM

The HSM Contains Best Science &

Research

• Synthesis of previous research

• New research commissioned by AASHTO and FHWA

III. HOW WAS THE HSM DEVELOPED?


The HSM – A Ten-year Research And Development Effort

19991999 20002000 20032003 FutureFuture

Research, research and more research

2010201020072007

Significant Effort & Professional Support

Produced the HSM• Joint

Subcommittee sponsored by 7 TRB committees

• Thousands of hours of volunteer effort

• Research program funded by NCHRP, AASHTO & FHWA

Research Path to the HSM v.1

IV. WHAT IS COVERED BY THE HSM?


Outline of the HSM

PART AINTRODUCTION, HUMAN FACTORS, &

FUNDAMENTALS

Part BRoadway Safety Management Process

Network

Screening

Diagnosis

Countermeasure

Selection

Economic

Appraisal

Prioritization of

Improvement

Projects

4 5 6 7 8 9

Safety

Effectiveness

Evaluation

Part CPredictive Method

• Methodology• Applications • Safety issues not

explicitly addressed by the methodology

• Example problems• References

Special Part C Special Part C Common ProceduresCommon Procedures

• Calibration• Combining predicted

with observed crashes

Definition of HSM Terms

• Safety Performance Function (SPF) – a regression equation used for estimating the predicted crash frequency at a site for a given “base condition”

• Accident Modification Factor (AMF) – used to adjust the “base condition” in the SPF to specific site characteristics

• Calibration Factor (C) – adjusts average crash frequencies calculated from the SPF to local site conditions

Predicting Crashes – Defining Roadway Segments and

Intersections

HSM Regional SPF Calibration

Step 5 – Compute calibration factors for use in Part C predictive model

Step 1 – Identify facility types of interest

Step 2 – Select sites for calibration of each facility type

Step 3 – Obtain data for each facility type applicable to the calibration period

Step 4 – Apply the appropriate Part C predictive model to estimate expected crash frequency for each site during the calibration period

Part DAccident Modification Factors

V. WHO SHOULD USE THE HSM?


Who Should Use the HSM?

• Assess the system needs & identify projects/studies

• Program projects• Evaluate system-wide safety effects of

programs

• Define problem(s) and assist in scoping• Identify potential solutions• Assess or evaluate multiple alternatives and

expected quantitative safety effects • Aid in identification of a preferred alternative

• Evaluate safety of alternative design approaches• Assist in review & documentation of design

exceptions, variances and waivers• Inform decisions on construction staging, work

approaches, etc.

• Monitor operations to maintain balance among safety, mobility and access.

• Evaluate the effectiveness of implemented improvements

VI. WHEN WILL THE HSM BE AVAILABLE?


Implementation Schedule

Training & Outreach Activities

• Sept 2009 – Jan 2010– Conduct two or three multi-state pilot

courses• August 2009

– TRB Task Force Meeting• TRB 2010 Annual Meeting

– One-day workshop • Training materials, including “Train-the-

trainer” available upon HSM release

VII. WHERE CAN ONE FIND MORE INFORMATION ABOUT THE HSM?


http://www.highwaysafetymanual.org

DATA NEEDS GUIDE

http://www.highwaysafetymanual.org

Key Contacts

• AASHTO– Ken Kobetsky: [email protected], (202) 624-

5254– Jim McDonnell: [email protected], (202)

624-5448– Joel McCarroll: [email protected],

(202) 624-3632• AASHTO JOINT TASK COMMITTEE

FOR THE HSM– Don Vaughn, ALDOT,

[email protected], (334) 242-6319

Key Contacts

• TRB/ NCHRP – Rick Pain: [email protected], (202)334-2964– Chuck Niessner: [email protected], (202) 334-1431

• TRB HSM TF: Development of a Highway Safety Manual– John Milton, [email protected], (360)704-6363

• TRB HSM TF: User Liaison– Geni Bahar (User Liaison Subcommittee of the TRB HSM

Task Force): [email protected], (416) 932-9272• TRAINING

– Karen Dixon (PI of NCHRP Project 17-38): [email protected], (541) 737-6337

The End

Questions?

hsm use and training karen k. dixon, ph.d., p.e. oregon state university

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