1. Slide 1 ENCE688F and Highway Safety Manual Dr. Mohamadreza Banihashemi Senior Transportation Research Engineer II GENEX Systems University of Maryland Seminar November 2014

2. Slide 2 Seminar Breakdown ENCE688F: Highway Safety Fundamentals History and Trends History and Trends Definitions and Concepts Definitions and Concepts Crash Studies and Crash Data Crash Studies and Crash Data Crash Prediction Models Crash Prediction Models Major National Highway Safety Programs, HSM and SHRP2 Major National Highway Safety Programs, HSM and SHRP2 Software Packages, Databases (i.e., SHRP2 RID) Software Packages, Databases (i.e., SHRP2 RID) IHSDM, a Course Project IHSDM, a Course Project Implementation of the HSM in the IHSDM Software Highway Safety Manual (HSM) Overview Highway Safety Manual (HSM) Overview IHSDM Overview IHSDM Overview Relationship between HSM and IHSDM Relationship between HSM and IHSDM Use of IHSDM / HSM in Developing a Sustainable Highway System Use of IHSDM / HSM in Developing a Sustainable Highway System Questions / Discussion. Questions / Discussion.

3. Slide 3 ENCE 688F: Highway Safety Fundamentals A Graduate Course Focusing on  Highway Safety History and Trends  Definitions and Concepts  Crash Studies and Crash Data  Highway Safety Quantitative Evaluation  Crash Prediction Models  Major National Highway Safety Programs  Software Packages, Databases (i.e., SHRP2 RID)  Course Project (IHSDM Software).

4. Slide 4 This is not A Highways Safety Manual Course, or An IHSDM Software Course, or A SHRP2 Safety Program Training. This is a Course in Highway Safety Fundamentals including many components of the above!!

5. Slide 5 History and Trends Organizations:  Federal Highway Administration (FHWA) ●Federal-Aid Program ●MUTCD ●Software/Website Development ●Actively Supporting HSM  Transportation Research Board (TRB) ●Highway Safety Manual (HSM) 1 st Edition ●SHRP2 ●Toward HSM 2 nd Edition  American Association of State Highway and Transportation Officials (AASHTO) ●Highway Safety Manual (HSM) ●Some Other Programs ●HSM Publication and Support.

6. Slide 6 History and Trends -Continue ●Highway Crash Fatality Trend ●The First Period of Rising Automobile Use in the US ●First National Conferences on Street and Highway Safety ●Balanced Design for Safety, Design Speed Concept ●Early Studies on the Effect of Highway Geometry on Safety ●An Erroneous Study Result: “The Accident Prone Driver” ●National Programs of Research and Development.

7. Slide 7 Definitions and Concepts Introducing main highway safety concepts and measures:  Design Speed Concept and its Deficiencies  Nominal Safety Measures  Substantive Safety Measures  Surrogate Safety Measures (Diagnostic Safety) Operating Speed Near Crash.

8. Slide 8 Definitions and Concepts -Continue Major Factors Known as Causes of Crashes Human Vehicle Highway Environment Cause and Effect vs. Correlation Older drivers and crash severity Speed and crash severity.

9. Slide 9 Crash Characteristics  Highway Purpose and Functional Classification Mobility vs. Access  Functional Classification Effects on Highway Design  Design Factors Affecting Safety the Most  Some National Crash Characteristics and Trends.

10. Slide 10 Highway Characteristics and Safety Major Highway Characteristics by Functional Class  Traffic Volume  Traffic Control  Highway Geometry  Auxiliary Lanes  Roadside  Lighting  Speed Enforcement.

11. Slide 11 Intersection/interchange Characteristics and Safety Major Intersection Characteristics by Functional Class  Volume  Traffic Control  Intersection Layout/Skew Angle  Interchange Configuration  Turn Lanes/Islands  Lighting.

12. Slide 12 Roundabout, A New Type of Intersection  Traffic Circles (Rotaries)  Neighborhood Traffic Circles  Modern Roundabouts Yield control Channelization Geometric curvature to limit the speed  Safety Effect of Replacing Intersections with Roundabouts  New Researches on Roundabouts.

13. Slide 13 Types of Crash Data and Crash Studies  Observational vs. Experimental Data  Longitudinal vs. Cross Sectional Data  Panel Data  Before-and-After Data  Some Sources for Inconsistencies and Biases  Basic Types of Highway Safety Studies Naïve and Improved Before-After Studies Cross Sectional Studies Empirical Bayes Studies.

14. Slide 14 Crash Data, Sources  National highway Traffic Safety Administration (NHTSA) National Automotive Sampling System (NASS) Fatality Analysis Reporting System (FARS) Crashworthiness Data System (CDS) General Estimates System (GES)  Highway Safety Information System (HSIS)  Other State Data  GIS Data  NDS Data Collected in SHRP2 Project.

15. Slide 15 Common Types of Crash Prediction Models  Main Assumptions Crash count obeys Poisson probability law Estimates of crashes follow Gamma distribution  Most Common Models Negative Binomial Linear and Non-Linear Regression  Models with Crash Modification Factors Safety Performance Functions Crash Modification Factors  Empirical Bayes Process.

16. Slide 16 Highway Safety Manual (HSM)  Part A – Introduction & Fundamentals Chapter 1 Introduction and Overview Chapter 2 Human Factors in Road Safety Chapter 3 Fundamentals  Part B – Safety Process Chapter 4 Network Screening Chapter 5 Diagnosis Chapter 6 Selection of Countermeasures Chapter 7 Economic Appraisal Chapter 8 Prioritization of Improvement Projects Chapter 9 Safety Effectiveness Evaluation.

17. Slide 17 More on Highway Safety Manual (HSM)  Part C – Predictive Methods Chapter 10 Rural, Two-Lane Roads Chapter 11 Rural, Multilane Highways Chapter 12 Urban/Suburban Arterial Highways  Part D – Accident Modification Factors Chapter 13 Roadway Segments Chapter 14 Intersections Chapter 15 Interchanges Chapter 16 Special Facilities & Geometric Situations Chapter 17 Road Networks  Part C – HSM Supplement Chapter 18 Freeways Chapter 19 Ramps.

18. Slide 18 SHRP2 Safety Program  A Quick History  What Is Naturalistic Driving Study (NDS)?  Collecting NDS Data  SHRP2 Roadway Information Data (RID)  Collecting and Assembling RID  Using NDS in Conjunction with RID  Brain Storming.

19. Slide 19 Course Project, IHSDM Software  Highway Safety Concepts Used in Each Module  Setting Attributes  Mechanics of the Software  A Quick Review of Administrative Tool  Running the IHSDM Software  Reporting and Customizing Report Templates  Interpretation of Results.

20. Slide 20 Questions ?

21. Slide 21 Highway Safety Manual (HSM) Part C Implemented in IHSDM

22. Slide 22 HSM, Background, History, and Future  Joint Task Force sponsored by several TRB committees  Partnership Among AASHTO, TRB and FHWA  $7 Million/10 year research program  Thousands of hours of volunteer effort of reviewing  AASHTO Joint Task Force with members from Safety, Design and Traffic Engineering  Publication of the HSM by AASHTO (2010), Supplement (2014)  A new TRB Committee (Highway Safety Performance)  Works to complete HSM 1 st Edition and moving toward 2 nd Edition.

23. Slide 23 HSM Partitions into Part A Introduction, Human Factors, and Fundamentals Part B Roadway Safety Management Process Part C Predictive Method Part D Crash Modification Factors

24. Slide 24 Concepts Nominal Safety Substantive Safety Examined in reference to compliance with standards, warrants, guidelines and sanctioned design procedures The expected or actual crash frequency and severity for a highway or roadway

25. Slide 25 What is IHSDM?  A product of FHWA’s Safety Research and Development Program  A suite of software tools that support project-level geometric design decisions by providing quantitative information on the expected safety and operational performance  Free Distribution and Support, First Release 2003, Latest Release 2014.

26. Slide 26 Evaluation Modules  Crash Prediction  Policy Review  Design Consistency  Intersection Review  Traffic Analysis  Driver/Vehicle

27. Slide 27 Crash Prediction Module Faithful implementation of the HSM Part C Estimates expected crash frequency (i.e., Substantive Safety) as well as crash severity based upon roadway geometry and traffic volumes.

28. Slide 28 Relationship between IHSDM and the HSM A.Introduction and Fundamentals B.Roadway Safety Management Process C.Predictive Method (IHSDM CPM) Chapter 10:Rural, Two-Lane Roads Chapter 11:Rural, Multilane Highways Chapter 12:Urban & Suburban Arterials Chapters 18 and 19: Freeways and Ramps. Recently published as supplements to the 1 st edition of the HSM. D.Crash Modification Factors.

29. Slide 29 CPM / HSM Part C Scope From AASHTO Website: An Introduction to Highway Safety Manual

30. Slide 30 CPM / HSM Part C Scope - Continue HSM ChapterUrbanRural 18 Freeway Segments10 Lanes8 Lanes 18 Speed-change Lanes10 Lanes8 Lanes 19 Ramps and C-D Roads 2 Lanes1 Lanes 19 Ramp Terminals7 Types

31. Slide 31 Models Components  Safety Performance Functions (SPFs)  Crash Modification Factors (CMFs)  Empirical Bayes (using crash history data)  Calibration Factors Enter via IHSDM Administration Tool.

32. Slide 32 Maximizing Safety Improvement Benefits in A Sustainable Highway System Cost, the Factor in Decision Making Construction Cost Operational Costs, Users Cost Environmental Costs Crash Cost.

33. Slide 33 Maximizing Safety Improvement Benefits in A Sustainable Highway System Continue Network-level Maximization, Part B of the HSM From AASHTO Website: An Introduction to Highway Safety Manual

34. Slide 34 Maximizing Safety Improvement Benefits in A Sustainable Highway System Continue Project-level Maximization, Part C of the HSM  Predicting Crashes for Different Alternatives  Estimating Construction, Operational, Environmental, and Crash Costs for Different Alternatives  Search for the Alternative with the Minimum Total Cost.

35. Slide 35 Other IHSDM Modules, Policy Review Checks roadway segment geometry against relevant design policy and “flags” variations.

36. Slide 36 Other IHSDM Modules, Design Consistency Estimates 85th percentile speed profile along alignment to evaluate operating speed consistency.

37. Slide 37 Other IHSDM Modules, Traffic Analysis  Traffic simulation model (TWOPAS)  Estimates traffic quality of service measures.

38. Slide 38 Other IHSDM Modules, Driver / Vehicle  Simulates driving behavior and vehicle dynamics on a two-lane highway  Provides profiles of predicted speed and other response variables, via a simulation of a single driver/vehicle combination.

39. Slide 39 Other IHSDM Modules, Intersection Review  Expert system that applies rules of good practice in a comprehensive diagnostic review of a single intersection  Identifies possible safety concerns and typical treatments.

40. Slide 40 IHSDM 2014 Release (10.0.0)  May be downloaded free-of-charge at: http://www.ihsdm.org http://www.ihsdm.org  Technical support: E-mail: IHSDM.Support@fhwa.dot.gov IHSDM.Support@fhwa.dot.gov Phone: (202)-493-3407  IHSDM Training (Offered by NHI): FHWA-NHI-380071 On-site Course FHWA-NHI-380100 Web-based Course ( http://nhi.fhwa.dot.gov ) http://nhi.fhwa.dot.gov