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

9 Source: FHWA

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

40 Source: Microsoft clip art

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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

jerry.roche@dot.gov

*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