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1
Introduction:Overview of Roadway Safety Management
Safety Analysis in a Data-limited, Local Agency Environment:
July 22, 2013 - Boise, Idaho
Module 1
2
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
3
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
7
Different approaches to safetyData-driven and science-based
Site-specificIdentify target crashes
Identify, evaluate and implement countermeasures
Systemic
8
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
5-14
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
5-15
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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
21
End Module 1
Questions?
22