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Introduction:Overview of Roadway Safety Management

Safety Analysis in a Data-limited, Local Agency Environment:

July 22, 2013 - Boise, Idaho

Module 1

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Introduction:Learning Objectives

Define nominal and substantive safety Discuss different approaches to safety

projects Define key steps of the roadway safety

management process Introduce safety analysis tools

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Introduction“Road safety management is in transition. The transition is from action based on experience, intuition, judgment, and tradition, to action based on empirical evidence, science, and technology…”

Ezra Hauer (May 2005)

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How do you define Safety?

Definitions of Safety Personal – Do I feel safe?

Based on personal experiences Level of comfort or discomfort

Engineer – design meets standards and/or crash frequency below threshold

Legislation – Fatal and injury crashes

Nominal vs Substantive Safety

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Which model more closely resembles what stakeholders are likely thinking?

11-ft lanes

12-ft lanes

A facility may be “nominally safe” but have a lower actual safety performance (i.e. substantive safety)

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Systemic approaches

Thinking out of the Box

Opportunities to Optimize Safety

Benefits

Low Cost Improvem

ent Opportunit

ies

Benefits through Systematic

ImprovementsTraditional Practice

Opportunities

During Project Scoping

and Design

Site-specific projects

Different approaches to safety

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Different approaches to safetyData-driven and science-based

Site-specificIdentify target crashes

Identify, evaluate and implement countermeasures

Systemic

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We know a low cost countermeasure that works, e.g rumble strips

Identify sites with characteristics appropriate for the low cost treatment

Implement the systemic treatment (always low cost)

Common data elements• Crash location, crash severity, roadway

conditions (lighting conditions, weather), date and time of the crash, users involved, vehicles involved, driver actions and condition (alcohol, drugs), and contributing circumstances

Crash data

• Number and widths of lanes, shoulder widths and types, roadway alignment (straight or curved), intersection configuration (number and types of lanes) and traffic control

Roadway data

• Traffic VolumesExposure

data9

Chapter 4

Chapter 5Chapter 6

Chapter 7Chapter 8

Chapter 9

Network Screening

Diagnosis & Countermeasure

Selection

Economic Appraisal & Prioritization

Safety Effectiveness

Evaluation

Roadway Safety Management Process HSM Part B (Chapters 4 – 9)

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• Establish Focus

STEP 1.

• Identify Reference Populations

STEP 2. • Screen and Evaluate Results

STEP 5.

Network Screening5 key steps

Desired Outcomes Identify contributing circumstances to crashes at

the site Understand site conditions Identify crash patterns Gain insight on countermeasure selection

Site diagnosis process STEP 1: Review safety data STEP 2: Assess supporting documentation STEP 3: Assess field conditions

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Selecting Countermeasures

Key Steps

Identify contributing factors to crashes

Select potential countermeasures or treatments

Apply counterme

asures

Identify Data Needs Assess Expected Project Benefits Estimate Project Costs Perform Economic Evaluation Consider Non-Monetary Impacts

Economic Appraisal

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Key Steps:

Project PrioritizationIs the alternative economically justified?

Prioritization Methods Ranking by economic effectiveness Incremental benefit-cost analysis Optimization methods

Remember though! include non-monetary considerations

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Implement and evaluate the effectiveness of countermeasures Implement countermeasures Evaluate countermeasures – how well is it

working for us? Should we do more of these projects? Are there ways to improve?

We can evaluate A single project at a specific location, or A group of similar projects, or A group of projects.

Potential resources & tools

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AASHTO Highway Safety Manual

usRAP

FHWA CMF Clearinghouse

FHWA Systemic Tool

Vol. 2 (Part C) Predictive Methods

Vol 3. (Part D) Crash Modification Factors (CMFs)

Highway Safety Manual

www.cmfclearinghouse.org 2-19

FHWA Systemic Safety Project Selection Tool

1. Identify Target Crash Types and Sites

2. Screen and Prioritize Candidate Locations

3. Select Countermeasures4. Prioritize Projects5. Identify Funding Source

and Implement Systemic Program

6. Evaluate Systemic Program

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Summary

Substantive safety is key to informed and defensible decisions

Approaches in roadway safety management allows for implementation at all levels of data availability

Resources and tools are available to support activities

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End Module 1

Questions?

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