Data-Driven Safety Analysis - TEXAS STATE …txstic.org/3.TXSTIC.Data Driven Safety...
Transcript of Data-Driven Safety Analysis - TEXAS STATE …txstic.org/3.TXSTIC.Data Driven Safety...
Data-Driven Safety Analysis
Integrating Safety Performance into ALL Transportation Investment Decisions
What’s happening?
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• Shrinking budgets • Growing lists of needs • Increasing fatalities • Establishing Safety performance measures
Credit: Bloomberg, http://www.bloomberg.com/news/articles/2016-08-29/u-s-highway-fatalities-increased-most-in-50-years-in-2015
We need to know how a roadway will perform in terms of safety
3 Source: Microsoft clip art, Wikipedia
What is DDSA? •The application of the latest evidence-based tools and approaches to safety analysis •Provides reliable estimates of an existing or proposed roadway’s expected safety performance •Helps agencies quantify the safety impacts of transportation decisions, similar to the way agencies quantify:
– traffic growth – environmental impacts – traffic operations – pavement life – construction costs
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Source: AASHTO, AASHTOWare, Roadway Safety Foundation
Foundational DDSA Methods: the AASHTO Highway Safety Manual, first edition
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2010 Release: •Rural Two-Lane Roads •Multilane Rural Highways •Urban/Suburban Arterials
2014 Supplement: •Freeway Segments •Ramps •Ramp Terminals
Source: AASHTO
A Document Akin To the HCM…
Definitive; represents quantitative ‘state-of-the-art’ information
Widely accepted within professional practice of
transportation engineering
Science-based; updated regularly to
reflect research
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The Vision for the HSM
6 Source: Transportation Research Board
The HSM has resulted in the development of:
• Spreadsheets
• Software Products
• Guidance Documents
• Crash Modification Factors Clearinghouse
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An Illustration of DDSA…
All three of these meet design standards…
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45 fatal and injury crashes/year 110 fatal & injury crashes/year 65 fatal & injury crashes/year
Alt 2 Alt 1 No-Build
but DDSA tells us they would perform very differently from a safety perspective.
Source: CH2MHILL
The EDC Data-Driven Safety Analysis Initiative…
Goal: Integrate safety performance into ALL transportation investment decisions
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Applying DDSA in Project Development Process
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Where can DDSA be applied in the Project Development Process?
Source: FHWA 11
DDSA in Planning 12
Source: FHWA
DDSA in the Planning Process
DDSA tools can be applied to help identify which roadways aren’t performing as they should, determine the scope and need of potential projects, and prioritize them.
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DDSA in the Planning Process
• System Level Planning • Network Screening
• Project Level Planning • Establishing Project Scope • Project Prioritization
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What is Network Screening?
• i.e. Which sites have the most potential for safety improvement?
Steps 1. Establish focus 2. Identify network 3. Select performance measures 4. Select screening method 5. Screen and evaluate results
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Traditional vs. Advanced Network Screening From simple safety performance measures: • Crash frequency • Crash rate • Equivalent property damage only (EPDO) To advanced safety performance measures: • Excess Predicted Average Crash Frequency • Level of Service of Safety • Potential for Safety Improvement • Systemic Sites with Promise
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Level of Service of Safety
Tool: Agile Assets Safety Analyst
Credit: Montana DOT
Example: MT DOT - Network Screening
DDSA in Alternatives Analysis 18
Source: FHWA
DDSA in Alternatives Analysis
DDSA tools can predict the number and severity of crashes for each project alternative, allowing safety performance to be considered along with other project criteria.
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Integrating Safety into NEPA Analysis
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http://safety.fhwa.dot.gov/tsp/fhwasa1136/fhwasa1136.pdf Source: FHWA
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Source: FHWA
When might a more-robust safety analysis in the environmental phase be appropriate?
• When Safety is included in the Purpose and Need
• Projects that claim a safety benefit
• Projects where there could be a substantial difference in safety for the alternatives being considered
• Projects with existing safety issues
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Example: LA DOTD – EIS Alternatives Analysis
I-12 to Bush, LA Four alternatives were considered to replace a two-lane, un-divided roadway with a four-lane, divided roadway with controlled access • All four alignments
predicted a reduction in crashes from the No Build alternative
Credit: Urban Systems, Inc. and Louisiana DOTD
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Potential Reduction in Crashes, Costs
Example: LA DOTD – EIS Alternatives Analysis
Credit: Louisiana DOTD
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Benefits from use of IHSDM • Quantify safety costs and benefits • Safety given equal weight in comparative
analysis
Corps of Engineers selected Alternative Q, which had a predicted crash reduction of 6% and a $1.5M cost savings to society
Example: LA DOTD – EIS Alternatives Analysis
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DDSA in Design
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Source: FHWA
DDSA in the Design Process
DDSA can be used to determine optimal design criteria, considering both safety and cost. • DDSA helps justify
flexibility in design • design exceptions • performance-based
practical design
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Example: AZ DOT Analysis of Design Criteria
Alternative Improvements Included: • Widening to 5 ft shoulders • Widening to 8 ft shoulders
(MP 441 to 466)
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Credit: Arizona DOT
Plot of Geometric Features and Expected Crashes Example: AZ DOT Analysis of Design Criteria
Credit: Arizona DOT
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Crash Prediction Results Example: AZ DOT Analysis of Design Criteria
Safety Analysis: • Model was un-calibrated as used (not necessary for
comparative alternatives analysis) • Alternative B (8-ft shoulders) would reduce crashes
by 4 percent more than Alternative A (5-ft shoulders)
Credit: Arizona DOT
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Example: AZ DOT Analysis of Design Criteria
Economic analysis: • Although Alternative B (8-ft shoulders) could
provide the greater benefit in reduction in fatal and injury crashes, Alternative A (5-ft shoulders) would provide the greater return on investment and was selected as the preferred alternative.
Credit: Arizona DOT
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Example: MN DOT – Communicating PBPD US Hwy 10 Access Study
31 Source: Bolton & Menk Credit: Anoka County and Minnesota DOT
Example: MN DOT – Communicating PBPD US Hwy 10 Access Study
32 Source: Bolton & Menk Credit: Anoka County and Minnesota DOT
Construction, Operations, and Maintenance
Source: FHWA
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DDSA in Construction, Operations, and Maintenance
• Interstate Access Requests • Intersection Control
Evaluation (ICE) • Traffic Impact Studies • Work Zones • Part-Time Shoulder Use • Performance Management
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Performance Management
Seven National Goals (MAP-21) • Safety • Infrastructure Condition • Congestion Reduction • System Reliability • Freight Mobility and Economic Vitality • Environmental Sustainability • Reduced Project Delivery Delays
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State of Repair CRS Range
9.0 to 7.6 Excellent 7.5 to 6.1 Good 6.0 to 4.6 Fair 4.5 to 1.0 Poor
IRI Range (in/mi) 1 to 94 Good
95 to 177 Fair > 177 Poor
SRI Range Minimal Good
Low Minor Medium Moderate
High Severe 5% 5%
Evaluating bridge and pavement condition data alongside safety performance to prioritize projects
• Condition Rating System (CRS) – Structural: Loss of load carrying capacity or structural breakdown
• International Roughness Index (IRI) – Functional/Surface: Excessive roughness impacting functional usability and causing drive discomfort
• Safer Roads Index (SRI) – Safety Performance (PSI): Establishes safety risk based on historical severe crashes and exposure
Example: IL DOT - Performance Management
Credit: Illinois DOT
Safer Road Index & Performance Metrics
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Example: IL DOT – Performance Management
Credit: Illinois DOT
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Safer Road Index & Performance Metrics
Legend
Example: IL DOT - Performance Management Safer Road Index & Performance Metrics
Credit: Illinois DOT
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Available Resources to Advance Implementation
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What we offer
•Technology Transfer – Informational Guides – Videos – Presentations – Webinars – Training – Workshops
•FREE Technical Assistance for each state that participates (project and/or program level)
– Implementation Planning – Conducting/Reviewing Safety Analysis – SPF Calibration/Development
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DC
Federal Lands
Puerto Rico
DDSA assistance under EDC-3: 43 States, 130 Requests and counting…
Virgin Islands Source: FHWA
“A game changer in traffic safety”
42 http://www.ksl.com/?sid=29580676&nid
Source: KSL Broadcasting, Salt Lake City, UT,
For more information…
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Jerry Roche, P.E.
FHWA – Office of Safety 515.233.7323
*FHWA cites specific tools as examples of ways to implement safety analysis approaches, not as an endorsement of these tools over others.
https://www.fhwa.dot.gov/innovation/everydaycounts/edc-3/ddsa.cfm