1. Data-Driven Safety Analysis
Integrating Safety Performance into ALL Transportation Investment Decisions
Today we’re going to provide an introduction to Data-Driven Safety Analysis and how it can be used to integrate safety performance into ALL transportation investment decisions.

2. Agenda Overview of Data-Driven Safety Analysis DDSA in Planning
Alternatives Analysis
Design
Construction, Operations, and Maintenance
Assistance Available
Today, we’ll provide an overview of Data-Driven Safety Analysis. Then, we’ll talk about how agencies have been incorporating DDSA in planning, alternatives analysis, design, and construction, operations, and maintenance. You’ll also have the opportunity to hear from your peers about how they have implemented DDSA. At the end, we’ll talk about available resources and assistance to help your agency.

3. Innovation Overview
Thanks Beth for such an emphatic introduction to kick off our session. Let’s continue.

4. 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
DDSA is the application of the latest evidence-based tools and approaches to safety analysis.
These approaches use crash, roadway, and traffic volume data to provide reliable estimates of an existing or proposed roadway’s expected safety performance.
DDSA 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
Source: AASHTO, AASHTOWare, Roadway Safety Foundation

5. The EDC Data-Driven Safety Analysis Initiative…
Goal: Integrate safety performance into ALL transportation investment decisions
The Data-Driven Safety Analysis initiative provides tools and methods to help accomplish this, giving us confidence in what we can expect before we build a project.
DDSA helps you make more informed decisions,
allowing you to better target our transportation investments,
which will lead to fewer fatalities and serious injuries on our nations roadways.
Beth mentioned that DDSA was continuing under EDC-4. One area that will be more strongly addressed in Round 4 will be applying DDSA on Local Roads, where approximately half our fatalities occur. Our effort will include tools and resources for local data collection and integration, development of Local Road Safety Plans, and project-level safety analysis.
Source: FHWA

6. Foundational DDSA Methods: the AASHTO Highway Safety Manual, first edition
2010 Release:
Rural Two-Lane Roads
Multilane Rural Highways
Urban/Suburban Arterials
2014 Supplement:
Freeway Segments
Ramps
Ramp Terminals
The foundational DDSA methods are contained within one primary document…the Highway Safety Manual. The HSM published by AASHTO compiled decades of research conducted by Transportation Research Board, State DOTs, and FHWA into one location. The first edition was published in 2010, which contained crash prediction models for rural two-lane roads, multilane rural highways, and urban/suburban arterials. The models for freeways and freeway interchanges were added in 2014 as a supplement.
Source: AASHTO

7. A Document Akin To the HCM…
The Vision for the HSM
A Document Akin To the HCM… 1
Definitive; represents quantitative ‘state-of-the-art’ information
Widely accepted within professional practice of transportation engineering
Science-based; updated regularly to reflect research 2
The vision for the HSM was akin to the Highway Capacity Manual…
The Highway Capacity Manual is acknowledged to be the recognized source of information and methodologies for quantitatively evaluating traffic operations on streets and highways. Engineering studies and reports that use the HCM are unquestioned with respect to the results. The HCM contents are based on peer-reviewed, science-based research; the HCM is continually updated and improved as more research is completed.
No such document exists in the field of quantitative highway safety. While there is quantitative safety information available, much of it is in conflict, may not reflect the best scientific methods, or is unclear in its contents and background. Engineers and planners who need to include quantitative safety information in their work are left to their own knowledge base and must not only make judgments about what data or methods to use, they must also defend their judgment.
The HSM is a toolbox for assessing quantitative safety effects of decisions or actions – nothing more. The HSM provides direction on how to use each of the tools contained within it, and how to interpret and communicate the results. It also provides direction on which tools are appropriate to use in a given situation or given the amount and quality of data available. The HSM provides the user with the tools to assess different alternatives to reduce crash frequency or severity.
With publication of an HSM, users can refer to it with confidence that it reflects best practices and knowledge and that it has been ‘vetted’ by highway safety research professionals. 3
Source: Transportation Research Board

8. The HSM has resulted in the development of:
Spreadsheets
Software Products
Guidance Documents
Crash Modification Factors Clearinghouse
The HSM has resulted in the development of spreadsheets, software products, guidance documents and the Crash Modification Factors Clearinghouse, all with the goal of helping automate the implementation of the approaches contained in the HSM.

9. An Illustration of DDSA…
All three of these meet design standards…
110 fatal & injury crashes/year
65 fatal & injury crashes/year
45 fatal and injury crashes/year
but DDSA tells us they would perform very differently from a safety perspective.
No-Build
Alt 1
Alt 2
On this slide, you see illustrations of possible design alternatives for a suburban arterial.
All three meet current design standards, and perhaps to the “naked eye”, some make think these designs would perform similarly.
That’s where DDSA can help. It shows that they would perform very differently from a safety standpoint. In fact, Alternative two would reduce fatal and injury crashes by 60%. These tools can helpful in informing us and our staff, informing elected officials, and even the traveling public.
Source: CH2MHILL, Integrating the HSM into the Highway Project development Process, FHWA May 2012.
Source: CH2MHILL

10. Where can DDSA be applied in the Project Development Process?
So where can DDSA be applied in the Project Development Process? Really, it can be applied throughout, and we’ve tried to boil it down to four broad stages. It can be applied in planning, alternatives analysis, design, as well as construction, operations, and maintenance.
We’ll talk more about these stages in a moment, but first I want to turn it over to my colleague, and co-team lead John McFadden from the FHWA Resource Center’s Safety and Design Technical Services Team. John, could you please lead us in a discussion about how we as professionals can provide “the highest and feasible level of safety”?
Source: FHWA

11. Applying DDSA in Project Development Process
The key here is to remember the crystal ball and that we can quantify how a roadway could, should, and will perform from a safety perspective.

12. DDSA in Planning
Thank you, Jerry. In this section, we will cover where safety fits into the planning process, for both system level planning and project level planning.
Source: FHWA

13. 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.
Planning sets the stage for the project development process and DDSA tools can be applied early in the planning process to help identify which roadways are not performing as they should, determine the scope and need of potential projects and prioritize them. 13

14. DDSA in the Planning Process
System Level Planning (Network Screening)
Predictive Analysis
Systemic Analysis
Project Level Planning
Establishing Project Scope
Project Prioritization
There are two distinct ways data driven safety analysis can be utilized in the planning process: system level planning and project level planning.
In system level planning, data-driven safety analysis can be used as a tool in screening your transportation network. In project-level planning, data driven safety analysis can be used in establishing project scope and prioritizing projects.

15. DDSA in Network Screening
Predictive analysis
Uses crash, roadway inventory and traffic volume data to provide more reliable estimates of an existing or proposed roadway’s expected safety performance
Every two years, FHWA works with the transportation community to identify a new set of innovations that merit widespread deployment through Every Day Counts (EDC). FHWA’s call for suggestions for EDC-4 innovations drew a strong response from stakeholders, who offered more than 80 new ideas. One of the innovations that received some of the highest marks was the continuation of our Data-Driven Safety Analysis initiative that began under EDC-3
DDSA helps you make more informed decisions,  allowing you to better target our transportation investments,  which will lead to fewer fatalities and serious injuries on nations roadways.
Systemic analysis
Uses crash and roadway data in combination to identify roadway characteristics correlated with particular crash types

16. Predictive Methods in Network Screening
Advanced Methods are More Reliable
Advanced methods account for potential bias due to:
Regression-to-the-mean
Changes in traffic volume
Nonlinear relationship between crash frequency and traffic volume
Differences in crash severity
FHWA recently published a series of informational guides entitled “The Reliability of Safety Management Methods”, one of which focused on Network Screening. To demonstrate the value of more reliable methods in network screening, crash locations in five states were tested using a combination of ten performance measures. In all cases, the expected average crash frequency with Empirical Bayes adjustments outperformed traditional measures such as crash frequency, crash rate, critical rate, and the level of service of safety (LOSS).
Srinivasan. R., Gross, F., Lan, B. and Bahar, G., “Reliability of Safety Management Methods: Network Screening,” Federal Highway Administration, FHWA-SA , 2016.
FHWA-SA

17. Level of Service of Safety
Example: Montana DOT - Network Screening
Level of Service of Safety
As an alternative to using more basic methods for evaluating safety, Montana DOT has performed advanced safety analysis for network screening by using the level of service of safety or LOSS method.
The LOSS method compares a roadway segment’s observed crash frequency and severity to the crash frequencies and severities predicted by safety performance functions. The comparison relies on the standard deviation of predicted crashes to assign a roadway segment to a particular level of safety. The four LOSS categories indicate a potential for crash reduction from high to low. As you can see from the locations plotted in red in the LOSS 4 category, Montana DOT identified a list of sites with high potential for safety improvement based on a potential for crash reduction, not the highest ADT or number of crashes.
Credit: Montana DOT
Tool: Agile Assets Safety Analyst

18. DDSA in Network Screening
Predictive analysis
Uses crash, roadway inventory and traffic volume data to provide more reliable estimates of an existing or proposed roadway’s expected safety performance
Every two years, FHWA works with the transportation community to identify a new set of innovations that merit widespread deployment through Every Day Counts (EDC). FHWA’s call for suggestions for EDC-4 innovations drew a strong response from stakeholders, who offered more than 80 new ideas. One of the innovations that received some of the highest marks was the continuation of our Data-Driven Safety Analysis initiative that began under EDC-3
DDSA helps you make more informed decisions,  allowing you to better target our transportation investments,  which will lead to fewer fatalities and serious injuries on nations roadways.
Systemic analysis
Uses crash and roadway data in combination to identify roadway characteristics correlated with particular crash types

19. The Systemic Approach…
Implements a system-wide screening of a roadway network based on the presence of roadway characteristics correlated with particular severe crash types, rather than high crash locations.
Source: FHWA Systemic Safety Project Selection Tool

20. A movement away from chasing dots (fatalities)…
Anystate, USA
2015
2016
2013
2012
2014

21. Limitations to the Site Analysis Approach
Crashes on rural roads often account for a high percentage of severe crashes, but the density of crashes on rural roadways is typically low and may not lead to identifying crash concerns within the “traditional” site-based analysis process.
And what the data shows us is that a majority of fatal crashes occur on rural roads and local roads. Crashes on rural and local roads are typically spread over hundreds or thousands of miles of in a state, making it more difficult to isolate high crash locations.
******************************
However, while effective, the site analysis approach has its limitations. A quick review of the national crash data establishes two key points. First, fatal crashes are overrepresented in rural areas – the National average is 57 percent. Second, a substantial number of these crashes are on the local system – the National average is 43 percent. Crashes on rural and local roads are typically spread over hundreds or thousands of miles in a state and are not as densely clustered as crashes in an urban area.
About 57% of fatal crashes are on rural roads
A further challenge is that crashes on the local system might not have robust data to assist with identifying locations of concern

22. Systemic Approach
Particularly applicable when a significant number of severe crashes happen over a wide area:
Rural Roadways
Local Roadways
May focus on specific crash types
Cross-median
Pedestrian
Curve
May include treating locations that haven’t experienced severe crashes
Photo Source: FHWA

23. Example: Local Road Safety Plans (LRSPs)
Provide a framework for local practitioners to take a proactive stance to identify the specific or unique conditions that contribute to crashes within their jurisdictions
Utilize the 4 E’s as appropriate to address safety issues
Provide an excellent opportunity for agencies at all levels of government (local, State, and Federal) to work together to align and leverage resources to address those safety challenges

24. Systemic Approach to Safety
Example: Minnesota DOT - Network Screening
Systemic Approach to Safety
Source: FHWA

25. DDSA in the Planning Process
System Level Planning
Network Screening
Project Level Planning
Establishing Project Scope
Project Prioritization
Now let’s look at data driven safety analysis in the context of project level planning.
Establishing project scope and performing project prioritization are two areas where safety analysis can play a role in project level planning.

26. Establishing Project Scope
Typical process:
Assess the performance of the existing site
Condition/status of pavement, structures, congestion, safety, etc.
Propose improvements
Determine necessary funding and schedule
Done at a level commensurate with the type and scale of the project
A typical process for establishing project scope looks like this. First, assess the performance of the existing site through various analyses, one of which can be safety.
Then propose improvements and determine funding and schedule. An analysis of safety impacts is typically done at a level commensurate with the type and scale of project.

27. Example: Colorado DOT Safety Analysis in Scoping
The Transportation Safety Management & Operations (TSM&O) Evaluation consists of three parts
Safety, Operations, and ITS analyses
The TSM&O Evaluation makes recommendations for improvements related to Safety, Operations, and ITS
All projects require a TSM&O Evaluation.
Safety
Operations
ITS
TSM&O Evaluation
Recommendations
An example of safety analysis in project level scoping can be found in Colorado DOT’s Transportation Safety Management and Operations Evaluation (or TSMO) process. Colorado DOT uses DDSA along with operations and ITS, in all projects as part of the TSMO evaluation. The evaluation results in recommendations for improvements that may be incorporated into the project.
And since all projects require a TSMO evaluation, safety plays a role in project level scoping for all projects.
Improvements Incorporated in Project
Credit: Colorado DOT

28. Safety Analysis in Project Prioritization
Typical process:
Identify criteria for scoring projects
Develop list of potential projects
Apply scoring methods for each criteria
Rank and prioritize list of projects
The second use of DDSA in project level planning is project prioritization. The typical process for project prioritization begins with identifying criteria for scoring projects, followed by developing a list of potential projects, then applying scoring methods for each criteria and ranking and prioritizing the list of projects.

29. Example: Virginia DOT – Safety Performance in Project Prioritization
Project Weighting Factors
Virginia DOT considers safety among other needs, such as congestion mitigation, accessibility and land use, when prioritizing projects. As part of their program SMART SCALE, Virginia is divided into categories based on urban and rural characteristics. Each project’s needs are given a weight dependent upon that category. For example, safety has a lower weight in category A, which is an urban area where data shows safety is less of an issue, and safety has a higher weight in category D, which is a rural area of the state where data shows safety needs more weight in consideration.
Credit: Virginia DOT
Factor
Congestion Mitigation
Economic Development
Accessibility
Safety
Environmental Quality
Land Use
Category A
45% 5%
15%
10%
20%
Category B
25%
Category C
Category D
35%
30%

30. DDSA in Alternatives Analysis
Source: FHWA

31. 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. 31

32. Integrating Safety into NEPA Analysis
Policy/Stakeholder Involvement
Source: FHWA
So what the graphic shows is our normal steps in developing a NEPA document …on one side of this process are steps in the safety evaluation, and on the other engagement with your project stakeholders. As we know the process starts with project scoping, and developing a purpose and need statement, then evaluating alternatives, and finally assessing the impact, benefits, and potentially mitigation if appropriate.
The safety performance of the project certainly has social, economic, and environmental impacts.
Here the key takeaway is that you can use these safety tools to really craft your purpose and need, and use it to evaluate project benefits.
Source: FHWA

33. 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
So when might a more robust safety analysis in the environmental or alternative analysis phase be appropriate?
Our advice is to really start to focus in on those projects where safety is strongly stated in the purpose and need, or where there is a project that claims a safety benefit, or where there are substantial differences between alternatives.

34. Purpose and Need example…
Level 2 Alternatives Evaluation Matrix
Evaluation Criteria
No-Build Alternative
Alternative 1
Alternative 2
Alternative 3
Infrastructure Condition
Ability to preserve or enhance infrastructure
Poor
(pavement rated “poor” in 2010)
Good
(new pavement)
Safety Improvements
Ability to implement safety features and reduce crashes
(narrow shoulders, steep slopes, inadequate clear zone would remain)
(Enhanced safety features would be included)
Construction Cost Estimate
2016 dollars
N/A
$17,300,000
$18,500,000
$21,600,000
Now we can all think of at least one purpose and need statement that was lacking, perhaps more if we’re willing to admit. So what we have here is one project recently reviewed where we had two primary needs - pavements and safety.
We have three alternatives which differ in cost by $4.3M. Now we’re going to leave it to the pavement and materials folks to comment on the infrastructure need and I’ll just focus on the safety section and lack of data or objective evidence.
This graphic was pulled from the NEPA document. And what we originally had in the purpose and need discussion, and we’ll paraphrase here, was that we had a task force convince some pretty important people that we had a major safety problem so we got some federal dollars earmarked for safety, and pavements.
So what you can see here are three alternatives that are actually different alignments and you can see the lack of substantive information to distinguish these three alternatives.
So although the cost of the project was well over $17M (and a range in cost of $4.3M) there was little to actually quantify the safety need or benefit. Whereas the point of DDSA is to make more informed decisions, so we can target our investments, with the ultimate goal of reducing fatal and serious injuries.
So we all hear everyone is trying to be cost conscious, and that budgets are tight, and we also hear everyone say safety is job #1 but here we have a $4M spread with no notable differentiation in performance. Not the best example.
***For illustration purposes only***

35. Example – Burlington County, New Jersey Intersection
So here is a good example from Burlington County, New Jersey where a signalized intersections and roundabout were two alternatives considered. This was actually developed into one of our feature EDC case studies which captures a more collaborative process between FHWA , New Jersey DOT, Burlington County, and the DRVPC (Deleware Valley Regional Planning Commission).
Credit: Burlington County

36. Evaluating Intersection Alternatives
Example: Burlington County, NJ
Evaluating Intersection Alternatives
Source: FHWA

37. Example – Burlington County, NJ Intersection Signalized Intersection
Alternatives Analysis: signalized Intersection vs. Roundabout
Feb 2012: fatal crash involving school bus occurs
Sept 2012: HSIP funding would require HSM analysis
Oct 2012: DVRPC offers to assist Burlington County with HSM Analysis
Jan 2013: HSIP project application submitted & approved
Jun 2014: Roundabout opened to the public
In 2012 this location saw a very gruesome crash involving a school bus and dump track which made national headlines. The location was a stop controlled intersection, and one of the fatals onboard was actually the daughter of a state trooper. Tragedies like this make for a very emotionally charged situation. In this case also NTSB got involved, along with other locally elected officials, and the greater community who were immediately calling for a signal to be installed which highlights another important aspect of DDSA, the ability to de-escalate some emotionally charged and sometimes subjective conversations regarding safety.
Additionally in this local area roundabouts, or the modern roundabout which is a proven safety countermeasure was considered new technology. But lucky for this project there were great champions at DVRPC and Burlington County to help navigate this concern and bring this project to the finish line.
Advance to alts 1 and 2: So because HSIP funds were being targeted an HSM analysis also needed to be completed to support the application.
This analysis really highlighted the difference in benefits between the two alternatives, which was then carried into the benefit/cost calculation which helped bring some confidence into the decision making process and get everyone on-board with the preferred alternative. What was a lot of public outcry for signals, turned into public support and acceptance of a roundabout. All in somewhat short order. So in about a year actually the evaluation was completed and the project was approved. And then in June of 2014 it was opened to the public.
So if you look at the graphic it is pretty clear that the ability to quantify safety allows us to start having more meaningful conversations and start making better targeted investments.
Alternative 1
Signalized Intersection
Alternative 2
Modern Roundabout
Benefit
(Crash Reduction)
$587,657
$1,296,097
Cost (Construction)
$1,113,029
$1,090,950
Benefit/Cost Ratio
0.53
1.19
Credit: New Jersey DOT 37

38. Example: Louisiana 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

39. Example: LA DOTD – EIS Alternatives Analysis
Potential Reduction in Crashes, Costs
As you can see the 5 alternatives were also ranked with the top being the best performer from a safety perspective and the no build the worst. You can also see the analyst period was twenty years out to 2035.
Credit: Louisiana DOTD

40. Example: LA DOTD – EIS Alternatives Analysis
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
Another interesting piece of this analysis was working across multiple resources and resource agencies include the Army Corps led the project team to select alternative Q.
So again using DDSA or the crystal ball does not force you to select an alternative but it does allow you to quantify safety performance, and have a much richer discussion on impacts across alternatives.

41. DDSA in Design
Source: FHWA

42. 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
Will be discussing how DDSA can be used during the design process, particularly for evaluating design exceptions and implementing performance-based practical design.
Performance-based practical design implemented with DDSA has great potential. State and local agencies have way more needs and problems to solve than available funding. Performance-based practical design using DDSA can result in projects that are much more cost effective. This allows limited funds to be stretched further and many other needs across the highway system can be addressed.

43. Performance-based Practical Design
An approach to decision-making that encourages engineered solutions rather than reliance on maximum values or limits found in design specifications
Characteristics
grounded in performance management
exercises engineering judgment to address purpose and need
uses appropriate performance-analysis tools
considers both short- and long-term project and system goals
Performance-based practical design, coupled with DDSA, offers great potential for developing more cost-effective projects. Rather than defaulting to standard values in tables or choosing design dimensions that have seemingly worked well in the past, PBPD and DDSA offer a more sophisticated approach where design values and dimensions are derived from analysis. And rather than looking only at individual projects, PBPD looks at needs across the entire transportation system.

44. DRAFT HSM Lite - V1 Overview
11/8/2018
Example: AZ DOT Analysis of Design Criteria
(MP 441 to 466)
A simple PBPD example from NE Arizona. 2-lane rural highway with very minimal shoulders (0-1 ft). DDSA was used to evaluate widening shoulders to either 5 ft or 8 ft.
Credit: Arizona DOT
Alternative Improvements Included:
Widening to 5 ft shoulders
Widening to 8 ft shoulders 44

45. DRAFT HSM Lite - V1 Overview
Example – Arizona DOT
11/8/2018
Plot of Geometric Features and Expected Crashes
Software tools are available to make DDSA more efficient during design. Arizona used the Interactive Highway Safety Design Model, which allows CADD files to be imported. The output in the bottom graph shows expected crashes by segment. The red line is the existing, minimal shoulders. The blue and green lines are the 5 and 8 foot shoulder options. The model shows significant improvement from the existing condition but a very small difference when comparing 5 ft vs 8 ft.
Once alignment, traffic, and other data are entered into these software tools, it’s easy to look at a wide array of design dimensions. For example, the safety impact of various increments of lane and shoulder widths can be compared.
Credit: Arizona DOT 45

46. DRAFT HSM Lite - V1 Overview
Example – Arizona DOT
11/8/2018
Crash Prediction Results
Credit: Arizona DOT
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)
The 8-foot shoulder option does have the lowest number of predicted crashes. The right-hand column shows a 21% crash reduction as compared to 17% for the 5-foot option (a small difference). This illustrates the sophistication of making design decisions with DDSA. This is a better approach than using “standard” values from Road Design Manuals or the AASHTO Green Book. It makes decision decisions more quantitative and objective, rather than opinion-based. 46

47. DRAFT HSM Lite - V1 Overview
Example – Arizona DOT
11/8/2018
Credit: Arizona DOT
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.
When you bring cost into the equation, the 5-foot option comes out on top with a B-C ratio of 2.3 compared to 1.9 for the 8-foot option. The more cost effective design was chosen, freeing up funds to address safety or other needs on Arizona’s system. 47

48. Example: MN DOT – PBPD US Hwy 10 Access Study
A larger example of using DDSA with performance-based practical design from MN. US Highway 10 is a high volume signalized expressway in suburban Minneapolis. The 7-mile corridor has ADT that ranges from 33,000 to 61,000 vpd. Over 10 years there were 13 fatal crashes, including 4 pedestrians. Many site constraints—adjacent BNSF rail line, high ROW costs, many access points.
Previous studies all looked at conversion to a freeway. The cost estimate to do this (including ROW) is $300 million. A study was initiated that took a step back from this freeway vision and looked at more cost-effective designs, that could more realistically be funded and constructed, and still achieve most of the operational and safety benefits of a full freeway.
The two layouts are examples of some of the designs considered. The bottom layout shows some alternative at-grade solutions. The top layout provides an overpass but with right-in/right-out connections, maintaining the expressway character of the highway, but with some grade separation.
This first graph shows the cumulative operational benefits achieved by implementing groups of these lower-cost projects. Implementation through the “mid-term priority” group of projects (the green line) would achieve 90% of the operational benefits of full freeway conversion. At $100 million, or one-third the cost!
Source: Bolton & Menk
Credit: Anoka County and Minnesota DOT

49. Example: MN DOT – Communicating PBPD US Hwy 10 Access Study
This second graph shows how DDSA was used to quantify the cumulative safety benefits, similar to how the operational benefits were quantified. Implementation through the “mid-term priority” group of projects (again, the green line) would achieve about 90% of the safety benefits of full freeway conversion. At $100 million, or one-third the cost!
Source: Bolton & Menk
Credit: Anoka County and Minnesota DOT

50. Construction, Operations, and Maintenance
Source: FHWA

51. DDSA in Construction, Operations, and Maintenance
Interstate Access Requests
Intersection Control Evaluation (ICE)
Traffic Impact Studies
Work Zones
Part-Time Shoulder Use
Performance Management
DDSA can be used in a more informed decisions in the construction
I want to quickly address the three examples shown in black.
First DDSA can be used to evaluate the safety impacts and safety cost associated with road improvements made as part of land development on it –
projects and identified in traffic impact studies.
Second, through the transportation management plan the safety impacts can sometimes be evaluated using DDSA.
Finally, operational techniques such as part-time shoulder use can be justified using DDSA.

52. Interstate Access Requests FHWA Policy Point #3
3. An operational and safety analysis has concluded that the proposed change in access does not have a significant adverse impact on the safety and operation of the Interstate facility …
Source: FHWA
Requests for a proposed change in access must include a description and assessment of the impacts and ability of the proposed changes to safely and efficiently collect, distribute and accommodate traffic…
>> Let's start with interstate access requests.
Assessing the operational and safety impact of new or modified interstate access is a critical element in preserving the function of the interstate highway system.
Access changes cannot have a significant adverse impact on the safety of a State Facility.
This is based on current and future your traffic projections.
Also requests must include a description an assessment of impacts and ability of our post changes to safely collect and distribute traffic.
For both current and future your traffic projections.
DDSA can provide a quantitative research base method for determining and documenting the safety impact of interstate access changes.
74 FR 165, pg (2009)

53. Would you expect these alternatives to perform the same over a 30-yr project life? Shouldn’t we know how alternatives will perform from a safety perspective before investing millions of taxpayer dollars?
Source: CH2M
>> So what you expect these alternatives to perform the same over 30 year project life?
Interchanges will perform differently from a safety perspective over the life of the design and given the context and conditions of the project.

54. Example: OH DOT Interchange Access Request I-270/US 33 Interchange, Dublin OH
Three of eight interchange alternatives were developed and analyzed based on a list of criteria:
Traffic Operations
Design & Construction
Environmental Impacts
Right-of-Way Needs
Capital Costs
Safety Performance
Source: CH2M

55. Safety performance analysis:
Example: OH DOT – Interchange Access Request I-270/US 33 Interchange, Dublin OH
Safety performance analysis:
Model was un-calibrated as used
Results used for comparisons are relative
Focused on KAB type crashes from
Alternative 8 predicted to have lowest KAB crash frequency and lowest expected societal cost
City of Dublin and ODOT selected Alternative 8 as the preferred alternative based on all of the criteria.
Source: CH2M

56. Intersection Control Evaluation
Purpose: Consistently consider and screen from among many proven combinations of geometry and traffic control when a new intersection or existing intersection modification is first contemplated.
Goal: to identify and select an alternative that both meets the project purpose and reflects the overall best value, in terms of specific performance-based criteria within the available limited resources.
>> DDSA can be applied with the intersection control evaluation framework, otherwise known as ICE.
ICE is a process that a growing number of transportation agency use to provide a more holistic approach to intersection control.
Far too often there is a bias in policy or Ewa individual engineering decision-making towards a particular intersection solution.
The use of DDSA can assist in quantifying safety among other factors within the ICE framework.
As it was previously shown in the New Jersey example, quantitative safety analysis can help make analytically informed decisions.

57. Example: Washington DOT - ICE Policy
WSDOT Design Manual M
Compare the predicted crash frequency of the alternatives using the tools described in Chapter 321. Discuss how each proposed solution might affect safety performance and crash types.
>> This is example from Washington DOT ICE policy.
In their design manual, a comparison of the predicted crash Birkins the of different alternatives is to be performed to.
And a discussion of how each solution impact of safety performance a different crash types, it is to be provided as part of the design analysis.
Credit: Washington DOT

58. 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
>> Finally, the last application I would like to present his performance management and its relationship with maintenance, projects, and DDSA.
Map21 defined goals for the seven performance areas shown here in scoping and prioritizing projects. Some States are evaluating multiple performance simultaneously as a way to meet a variety of goals.
Maintenance projects provide a great opportunity to address multiple system performance measures and targets.

59. Example: IL DOT – Performance Management
Safer Road Index & Performance Metrics
Credit: Illinois DOT

60. Example: IL DOT - Performance Management
Safer Road Index & Performance Metrics
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
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
95 to 177
> 177
SRI Range
Minimal
Low
Minor
Medium
Moderate
High
Severe 5%
Credit: Illinois DOT

61. Example: IL DOT - Performance Management Safer Road Index & Performance Metrics
Legend
Credit: Illinois DOT

62. Integrating Safety Performance

63. Assistance Available to Advance Implementation

64. EDC-3 DDSA performance metrics
32 presentations and workshops were made
10 DDSA “How-To” webinars were hosted
35 training workshops were conducted
30 marketing materials and articles were created
14 social media posts were made
3 videos were created, with 4 more in production
2 informational guides were created
4 software updates to IHSDM were released
7 peer exchanges were held involving 57 States (35 unique)
Provided in-depth technical assistance to 10 states
Assisted 44 States with 145 total requests for assistance
Our collective implementation accomplished quite in bit in a relatively short time period.

65. EDC-4 Goals (by Dec 2018)
Increase the number of States that have applied DDSA on one or more projects (demonstration level).
Increase the number of States that have integrated DDSA in their project development process (assessment or institutionalized levels).
Increase the number of States with crash, roadway, and traffic volume data collected and integrated on all public roads.
Identify and increase the number of local agencies with local road safety plans.
Increase the number of projects and percent of HSIP funding applied to local roads.
As far as EDC-4 goals, the first two remain the same from EDC-3. We’ve also added three more, as we increase our attention on the local system (where over half of the fatalities occur).

66. EDC-4 DDSA: DDSA Baseline and Goals Demonstration or Above
Assess or Above
Baseline 38 22
Goal 49

67. EDC-4 DDSA Status and 2-year Goals
State Fill: Current Status
Circle Fill: Goal Status
Federal Lands
(FLH) DC AL AR AZ CA CO FL GA IA ID IL IN KS KY LA ME MI MO MS MT NC ND NE NM NV OK PA SC SD TN TX UT VA WA WI WV WY OR NY MN AK VT MD DE NJ CT RI MA NH PR HI OH
Not Implementing
Development
Demonstration
Assessment
Institutionalized VI
Source: FHWA EDC-4 Baseline Implementation Progress Report -- as of February 17, 2017

68. What we can offer
Technology Transfer
Informational Guides
Presentations
Training Workshops
Peer Exchanges
FREE Technical Assistance for each state that participates (project and/or program level)
Implementation Planning
Conducting/Reviewing Safety Analysis
SPF Calibration/Development
Source: Microsoft clip art

69. For more information… Fact Sheets and Case Studies Infographics Videos
Webinars
Informational Guides
Training Workshops
Technical Assistance

70. Questions?
John Broemmelsiek, P.E.
FHWA – Louisiana Division
Betsey Tramonte FHWA – Louisiana Division
*FHWA cites specific tools as examples of ways to implement safety analysis approaches, not as an endorsement of these tools over others.