Highway Safety Analysis Tools for Engineers Safety...Highway Safety Analysis Tools for Engineers...

Highway Safety Analysis Tools for Engineers

Xiaoduan SunUniversity of Louisiana – Lafayette

Dan Magri

Hadi H. ShiraziLouisiana Department of Transportation and Development

The 2007 Louisiana Transportation Engineering Conference

Baton Rouge, February 12, 2007

Topics

1. Louisiana Crash Data Analysis Program

2. Introduction to Highway Safety Manual

Highway Safety Analysis: a data driven activity

As with all other aspects of transportation engineering,

highway safety analysis is becoming more data driven,

since data provide the most meaningful guidance in how,

where, and what happened in the real world - if they are

accurately collected. The technology advancements in

recent years have greatly enhanced the efficiency and

quality of crash data collecting process, which makes

safety analysis more data-dependent and reliable.

1. Louisiana Crash Data Analysis Program

Program Goal

Provide a crash data analysis tool for the

everyday traffic engineers in Louisiana who

need to perform safety analysis periodically

but have no extensive experience in database

and GIS applications

Overview of the Program Development

Phase I Phase II Phase III

Objectives

Develop a computer

program for accident

analysis on a GIS

platform

Make program an on-

line application and

further improve the

program to include many

newly proposed

functions

Add more analysis

functions such as selecting,

prioritize, and evaluating

the countermeasures, and

including urban area crash

data and independent

intersection crash analysis

Summary of the

accomplishments

Developed the first

version of a computer

program for Louisiana

crash data analysis on

a GIS platform, and

developed techniques

to incorporate video

image from the state

bi-annual pavement

survey.

Finished on-line

application;

reprogrammed the

system for flexible

analysis unit (segment

length) and user defined

analysis scheme;

applied HSM[ prediction

model to the selected

segments on Louisiana

rural two-lane highways.

HSM

on-going

An on-line application program

Scope of Crash Data Analysis

Program

• Conventional crash analysis– Spatial (where are the most promising sites)

– Temporal

– Characteristics

– Combination of all factors

– Black Spot identification

• Safety performance evaluation– Prediction vs. historical observation (rural two lane highways)

– Most Promising location identification

Results Presentation

•Charts

•Tables

•GIS maps

•Video

Program‟s Main Functions

General Analysis

time

space

Factors

A Particula highway

frequency

Rate

any legnth

Advanced Analysis

Map control

crash report

Lon in

Analysis Unit: a highway, a segment of

highway (by control section or by user defined length),

an intersection, or a network

Total crashes on rural 2-lane highways

Fatal crashes on rural 2-lane highways

Where are these fatal crashes?

Hit and run between 0 and 6am

Total hit and run

7% of total 2004 crashes

Had been drinking between 0 and 6am

Total # of “had been drinking” cases

Locations with one single

crash resulting 3 fatalities

77 crashes involved farm

equipments

76 Pedestrian fatalities

Red light running

So far, only safety performance function for

rural 2-lane highway is available from the on-

going project of Highway Safety Manual

Acknowledgement

Mr. Tom Richardson and Mr. Glenn Chustz from

Louisiana Department of Transportation and

Development.

The crashed server will be back to operationPlease leave your email for getting the address soon

2. The Development of Highway Safety Manual

Overview

• What is the need for a „Highway Safety Manual‟?

• What is the HSM?

• History on the Evolution of the HSM

• Organization and contents of the HSM

• HSM user survey results

Is this road “safe” or “unsafe”?

What about these alternatives? Is one „safer‟ than the others?

What about these choices? How do we address the safety of

these design options?

How do we make judgments about balancing

„safety‟ with other community values?Safety vs. Costs, environment, etc.

Trade-offs We Routinely Make

• Capacity versus safety

–Permitted versus protected signal

phasing

–Right turn on Red

• Economics versus safety

–2-lane versus 4-lane rural highways

–4-lane undivided versus divided

highways

–Access control (driveway permits)

• Modal choice versus safety

–Rumble strips versus shoulder use by

bicyclists

–We routinely “trade off” safety in

many decisions we make (ADMIT OR NOT)

–Safety is more than an abstract notion

–If safety is important and it varies, we should commit to including measures of safety in our evaluations

Putting „Safety‟ in Its Proper Perspective

Two Ways to Look at Safety as Highway Engineers and Planners

• Nominal Safety is examined in

reference to compliance with

standards, warrants, guidelines and

sanctioned design procedures (e.g.,

„The Green Book)

• Substantive Safety is the actual or

expected crash frequency and

severity for a highway or roadway

(i.e., its actual performance)

Complex decisions require meaningful tools for all important criteria

Safety Environmental Traffic Operations Right-of-Way CostsImpacts Impacts

•Traffic Noise

Model 1.0

•CAL3QHC

•Mobile 5a

•3-D Visualization

•CITYGREEN

•HCM

•MUTCD

•simulation

•Design

Specifications

•B/C analysis

methods

•Design

Criteria

(nominal

safety)

•Understand fundamental

substantive safety principles

•Perform substantive safety analyses

•Methods to predict substantive

safety (including and particularly

issues involving choices „on the

margin‟)

•Decision-making tools

What do potential users want/

need?

What is the Highway Safety

Manual (HSM)?• Purpose: To provide the best factual information

and tools in a useful form to facilitate roadway planning, design, operations, and maintenance decisions based on explicit consideration of their safety consequences.

– Synthesis of validated highway research

– Adapted & integrated to practice

– Analytical tools for predicting impact on road safety

The „vision‟ of the HSM -- a document akin to the HCM

• Definitive; represents

quantitative ‘state-of-the-

art’ information

• Widely accepted within

the professional practice

of transportation

engineering

• Science-based; updated

regularly to reflect

research

Targeted Users of the HSM

• Primarily users:

– Front-line decision makers

• Analysts studying the effect of actions on road users

• Planners, designers and those responsible for the

operations and maintenance

• Secondary users:

– Management

– Educational Institutions

History (1)

• Started with discussions within TRB about role of

safety in Highway Capacity Manual

• Conference Session at TRB’s January 1999

Annual Meeting concluded:

– The absence of, and the need for a single authoritative

document to use for estimating safety impacts

• December 1999 Workshop confirmed:

– The crucial need for a stand-alone document to be

named the Highway Safety Manual

History (2)

• Formation of a TRB Joint Subcommittee for the development of a HSM:

– Members of sponsoring committees

– AASHTO, FHWA, ITE

• Meetings since January 2000:

– About 100 members and friends

– Status 2003: Task Force (with six subcommittees)

Research & Development

• Task Force key objective to provide direction and oversight of research

• Relevant NCHRP effort:– 17-25: CRFs for Traffic Engineering & ITS Improvements 7/06

– 17-26: Part III: Urban & Suburban Arterials 2/07

– 17-27: Parts I & II (Intro & Knowledge) 5/07

– 17-29: Part III: Multi-lane Rural Highways 7/06

– 17-34: Parts IV & V (Safety Systems & Evaluation) 9/06

– 17-36: Production of the First Edition 2008

• Other related initiatives– IHSDM, SafetyAnalyst, Human Factors Guidelines

A New Era in

Highway Safety Analysis

• Modeling (SPFs) in First Edition HSM will be rudimentary

• Gaps in knowledge (AMFs)

• Encourage:

– Evidence-based decision making

– More resources focused on safety research

– Innovative approaches to improving safety

Outline of HSM First Edition

Part I – Introduction and Fundamentals

Part II – Knowledge

Part III – Predictive Methods

Part IV – Safety Management of a Roadway

System

Part V – Safety Evaluation

Glossary

Part I - Chapter 1

Introduction and Overview1.1 Purpose

1.2 Background on the Need for HSM

1.3 Scope of the HSM

1.4 Intended Audience

1.5 Intended use of the HSM

1.6 Context for the HSM: Use and Misuse of the Manual

1.7 Nature of the HSM

1.8 Organization of HSM

Part I - Chapter 2

Fundamentals2.1 What is Safety?

2.2 How Road Safety is Measured

2.3 Safety Performance, Crash Causation, Countermeasures, Accident Modification Functions

2.4 Human Factors in Road Safety

2.5 Traffic Exposure, Traffic Mix and Demand Management

2.6 Speed and Safety

2.7 Safety Evaluation

Part II - Chapter 3

Roadway Segments

3.1 Safety Effects of Design Elements

3.2 Safety Effects of Traffic Control and

Operational Elements

3.3 Pedestrian and Bicyclist Safety on

Roadway Segments

3.4 Safety Effects of Other Elements

Part II - Chapter 4

Intersections




4.3 Pedestrian and Bicyclist Safety at

Intersections


Part II - Chapter 5

Interchanges




5.3 Pedestrian and Bicyclist Safety at

Interchanges


Part II - Chapter 6Special Facilities & Geometric Situations

6.1 Railroad-Highway Grade Crossings

6.2 Work Zones

6.3 Bridges

6.4 Tunnels

6.5 Two-way Left-turn Lanes

6.6 Passing Lanes/Short Four-Lane Sections on Two-Lane Highways

6.7 Climbing Lanes

6.8 Emergency Escape Ramps

6.9 Rest Stops

6.10 High Occupancy Vehicle Facilities

6.11 Reversible Roadways & Lanes

6.12 Weaving Areas

6.13 Collector-Distributor Roads

6.14 Frontage Roads

6.15 Transit Facilities and Related Features

6.16 Bicyclist and Pedestrian Facilities and Related Features

6.17 Toll Plazas

6.18 Special Events

Part II - Chapter 7

Road Networks7.1 Introduction

7.2 Safety in Transportation Network Planning

7.3 Safety in the Planning and Design of

Residential Neighborhoods and Commercial Areas

7.4 One-Way Systems and Turn Restrictions

7.5 Safety in Traffic Calming

7.6 Access Management

7.7 Road-use Culture

7.8 Transitions between Highway Facility Types

7.9 Security (against Crime) and Safety

Part III - Chapter 8

Rural, Two-Lane Roads

8.1 Introduction

8.2 Methodology

8.3 Applications

8.4 Example Problems

8.5 References

8.6 Appendices

Louisiana Involvement

“Application of Highway Safety Manual Draft Chapter: Louisiana Experience”

-Journal of TRR, Published in 2006

ObjectivesTo evaluate the model with data from Louisiana to assess the

model‟s capability and transferability in predicting safety

performance of rural 2-lane highways.


Rural, Multi-Lane Highways

9.1 Introduction

9.2 Methodology

9.3 Applications

9.4 Safety Issues Not Explicitly addressed

by the Methodology


9.6 References


Urban/Suburban Arterial Highways

10.1 Introduction

10.2 Methodology

10.3 Application

10.4 Safety Issues not Explicitly addressed

by the Methodology


10.6 References

Part IV - Safety Management of a

Roadway SystemChapter 11 Identification of Sites with Promise

Chapter 12 Diagnosis of the Nature of Safety Problems at Specific Sites

Chapter 13 Selection of Countermeasures to Reduce Accident Frequency and Severity at Specific Sites

Chapter 14 Economic Appraisal of all Sites under Consideration

Chapter 15 Prioritized Rankings of Improvement Projects

Part V - Chapter 16

Safety Evaluation of Implemented

Measures

16.1 Introduction

16.2 Why Evaluate?

16.3 Data Needs and Limitations

16.4 Approach to Conducting a Valid

Evaluation

Challenges to HSM Development

• Must have good liaison with the potential

user community

• Must be cognizant to highway agency

concerns about tort liability

• Substantial funding and time needed to

produce the first edition HSM

User Survey Background

• A web survey conducted in 2002 by User

Liaison and Support Subcommittee

• Over 2000 invitations

• 288 complete responses

User Survey Results – Employment

Type

User Survey Results –

Participant Affiliation

User Survey Results –Priority of Topics in HSM

1st Safety Effects

2nd Safety Principles

3rd Measures of Safety

4th Methods to Predict Safety Impact

5th Decision-Making Tools

User Survey Results –Priority of Facility Types in HSM

1st Signalized Intersections

2nd Multilane Roads

3rd Two-lane Roads

4th Yield and STOP-controlled Intersections

5th Interchanges

User Survey Results –Applications for HSM

• System-wide and Planning Programs

• Integration with Training, University

Courses, and Association References

• Prepare Responses to Citizens & Politicians

• A Daily Reference – A Professional

Handbook (Interfacing with a Software)

Acknowledgements

HSM Task Force for the preparation of this part of

presentation

Questions ?

[email protected]

Thank You!

mailto:[email protected]

Highway Safety Analysis Tools for Engineers Safety...Highway Safety Analysis Tools for Engineers...

Documents

Transcript of Highway Safety Analysis Tools for Engineers Safety...Highway Safety Analysis Tools for Engineers...