Primer on the Joint Use of the HSM and HFG for Road Systems Using Human Factors to Guide Data-Driven Decision-Making

Transcription

1 Est. Dec Primer on the Joint Use of the HSM and HFG for Road Systems Using Human Factors to Guide Data-Driven Decision-Making Presented by: Contributors: John Campbell, Battelle John Milton, Washington State DOT Sam Tignor, Virginia Tech Alexander Maistros, Cambridge Systematics

2 Webinar Logistics Duration is 11:00 AM - 12:30 PM Mountain Webinar recorded and archived on website. For quality of recording, phone will be muted during presentation If listening on the phone, please mute your computer To maximize the presentation on your screen click the 4 arrows in the top right of the presentation At the end of each section, there will be time for Q&A There is a handout pod at the bottom of the screen Send group lists to info@ruralsafetycenter.org Please complete follow-up surveys; they are vital to assessing the webinar quality 2

3 Certificates of Completion/CEUs Survey Link 9i7m3/start Survey closes 2 weeks after webinar Expect certificate/ceu form 3-4 weeks after webinar Return CEU form to ContinuingEd@montana.edu NOT Safety Center Request a verification of completion form 3

4 Certificates of Completion/CEUs 4

5 Today s Presenter John Campbell, Battelle 5

6 Goals of this Webinar Once you have completed this webinar, you will: have an overview of the Primer on the Joint Use of the Highway Safety Manual (HSM) & the Human Factors Guideline (HFG) for Road Systems

7 Learning Outcomes To achieve the webinar goal, you will learn: Summarize the role of human factors in roadway design, operations, and safety? Incorporate the HFG and the HSM into the Data-Driven Decision Making Process Illustrate how to use the HSM and the HFG together to improve decision-making 7

8 John Campbell, Battelle Summarize the role of human factors in roadway design, operations, and safety? Incorporate the HFG and the HSM into the Data-Driven Decision Making Process Illustrate how to use the HSM and the HFG together to improve decision-making 8

9 What is Human Factors? Human factors is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. As applied to road safety performance, human factors considers and accounts for road user needs, capabilities, and limitations in: (1) the design and operation of roads, vehicles, and pedestrian/bicycle/transit facilities (2) the identification of causal factors underlying conflicts and crashes.

10 What road user capabilities and limitations does human factors address? Sensation Seeing, hearing, feeling Perception Reorganizing, organizing, making sense Attention Actively processing information Decision-making & Response Selection Response Execution Memory Deciding, selecting Acting, doing Retaining, recalling

11 Three Factors of Driving Human factors approach to driving involves three components: Road User Environment Vehicle

12 Three Factors of Driving (Cont.) These three components are inter-dependent Environment Road User Vehicle Road User Samples information from environment Controls vehicle Maneuvers through environment Environment Provides information to the driver Responds to the driver through actions of other road users Vehicle Triggers some responses in the environment Provides feedback to the driver

13 How can we apply human factors to roadway design, operations, and safety? Applying human factors is about examining the who, where, and the why of crashes. Human factors is more than the overt, specific behaviors that can lead to crashes, such as speeding, impaired driving, road rage, or intentionally engaging in distracting behaviors. Human factors also includes the relationships and compatibilities between: (1) the requirements of the driving task at a particular roadway location and under a specific set of circumstances and (2) the capabilities and limitations of the road user.

14 What is the Human Factors Guidelines for Road Systems (HFG)? The HFG is a resource for improving roadway safety performance that provides guidelines, data, and insights on road users characteristics to help guide design and operational decisions. Focus on road user needs, limitations, and capabilities Aid and augment the judgment and experience of highway designers and traffic engineers through presentation of factual information and insights from the human factors literature Complement existing sources of road design information The 2nd Edition of the HFG (NCHRP Report 600) was published in distinct guideline topics 475+ references PDF version with updated external and internal links 2-hour training course A downloadable version of the 2nd Edition HFG can be found here: Development of the 3rd Edition is underway

15 Presentation Format Used in the HFG 15

16 Directing Your Questions via the Chat Pod 1. Chat pod is on left side of screen between attendees pod & closed caption pod 3. Answers will appear here unless addressed verbally 2. Type your question or comment here

17 John Campbell, Battelle Summarize the role of human factors in roadway design, operations, and safety Incorporate the HFG and the HSM into the Data-Driven Decision Making Process Illustrate how to use the HSM and the HFG together to improve decision-making 17

18 Incorporate the HFG and the HSM into the Data-Driven Decision Making Process (1) Introduction to the HSM/HFG Primer

19 Primer on the Joint Use of the HSM and HFG The HSM is used to quantify the effects of safety decision-making on crash frequency and severity outcomes thus estimating the safety of roadway infrastructure. The HFG is used to facilitate safe operational decisions by providing the best factual information and insight on road users needs. Joint use of the HSM and the HFG will improve end users ability to select roadway design and operational elements based on the bestavailable data and promote an improve level of highway safety. How can the HSM and the HFG be used together to improve safety performance?

20 Primer on the Joint Use of the HSM and HFG (cont.) Purpose & Approach: facilitates the combined use of the HSM and the HFG to support improved countermeasure identification and selection a short, instructive, and readily useful document that explains the joint use of these resources, and provides state and local agencies a tool to enhance datadriven decision-making provides: (1) a general step-by-step description of joint use and (2) specific examples that will illustrate how the HSM and HFG can be used together in project development to promote the highest level of safety for new or upgraded roadways

21 A Process for Joint Use of the HSM and HFG (cont.)

22 Joint Use of the HSM and HFG Step 1: Collect Site Data Objective: Compile data necessary to assess the traffic safety performance at the intended site quantitatively and qualitatively. Key Activities: Obtain and organize data on crashes, traffic volumes, and recent projects that might impact safety. Carefully consider issues such as: Scale Timeliness Quality/Limitations Desired Outcome: A time-consistent collection of crash, traffic, and project data describing the safety, behavioral, and roadway data relevant to the site.

23 Joint Use of the HSM and HFG Step 2: Review Site and Existing Conditions Objective: Identify potential contributing factors to crashes from both a traffic engineering perspective and a human factors perspective. Key Activities: a) Conduct site visit what are the existing roadway and behavioral conditions? Outcome: A qualitative analysis of traffic, behavioral, and roadway issues at the site. b) Identify crash patterns/trends and contributing factors- what is the safety performance at the site by mode, year, crash type, and contributing factor? Outcome: A quantitative description of the safety challenges at the site with an understanding of the critical crash types, severities, and contributing factors c) Conduct human factors evaluation what are the possible HF issues that should be considered in developing robust, science-based safety solutions? Outcome: A Human Factors Interaction Matrix (HFIM) that is populated with possible road user, vehicle, and environment issues and their interactions that could be impacting the safety performance of the facility under investigation.

24 Joint Use of the HSM and HFG Step 3: Identify Potential Countermeasures Objective: Identify potential Countermeasures from the HSM and the HFG Key Activities: a) Identify countermeasures from the HSM involves using either the predictive method (Part C) or CMFs (Part D) to estimate the effects of various potential site treatments. Outcome: Quantitative estimation of potential impacts on crashes for each potential solution. b) Identify countermeasures from the HSM - Create a list of HFG contents corresponding to potential contributing factors to crashes included in the HFIM from Step 2 Outcome: A succinct summary of key road user issues, specific recommendations, countermeasures, or design options from the HFG, and any related information that will support a robust safety solution. c) If needed, conduct an additional site visit

25 Joint Use of the HSM and HFG Step 4: Develop and Prioritize Countermeasures Objective: To develop a prioritized list of potential countermeasures to the safety challenges identified in Step 2 of the process. Key Activities: a) Analyze and prioritize countermeasures from the HSM consider degree of confidence, benefits, impacts, conflicts, feasibility b) Synthesize and prioritize joint countermeasures from the HSM and the HFG What is the alignment between the engineering solution(s), the crash trends, and contributing factors identified in the diagnosis, and the human factors assessment? How do the recommendations from each source (the HSM and the HFG) relate to or complement one another? Given the overall situation, what recommendations from the two sources seem the most feasible from a safety, implementation, and cost perspective? Desired Outcome: A prioritized list of potential countermeasures that may be developed into actionable projects.

26 Joint Use of the HSM and HFG Step 5: Conduct Safety Effectiveness Evaluation Objective: To quantitatively assess the safety performance change of the completed project. Resources: The Crash Modification Factor Clearinghouse recommendations for developing CMFs. Observational Before-After Studies in Road Safety, E. Hauer, Outcome: A quantitative analysis of the effectiveness of roadway changes based on recommendations from the HSM and HFG.

27 Incorporate the HFG and the HSM into the Data-Driven Decision Making Process (2) Countermeasures from the Human Factors Guidelines for Road Systems (HFG)

28 Relative roles of driver, environmental, and vehicle factors in crashes (from Treat et al., 1979; see Figure 2-2) While drivers contributed to 93% of crashes, they were the sole cause of only 57% of crashes It is often the interactions between road users, vehicles, and the environment that lead to errors, conflicts, crashes, and fatalities Errors do not generally reflect the breakdown or occurrence of a single factor but, rather, reflect a confluence of factors that occur more or less simultaneously. We need to consider the full range of contributing factors that interact with a specific context and eventually lead to errors and crashes.

29 General Approach to Conducting Diagnostic Assessments 1. Identify driver information needs or road user limitations that could lead to errors, problems, or crashes (Step 2) 2. Identify/Describe these issues-why is it a problem? (Step 2c) 3. Identify/Describe potential interactions across issues (Step 2c) 4. Identify key information and countermeasures in the HFG (Step 3b)

30 The Human Factors Interaction Matrix (HFIM) The HFIM is a modified Haddon Matrix that we use starting in Step 2c to help identify road user and other factors that could be contributing to a reduction in road safety across a range of various scenarios and driving situations. Road User Vehicle Environment Interactions Relevant Sections in the HFG The HFIM is completed as we work our way through individual safety issues/contributing factors/crash sites 30

31 HFIM with factors that might contribute to reduced roadway safety performance Road User Vehicle Environment Vehicle type Steering capabilities Braking capabilities Engine characteristics Safety features Vehicle height Headlamps Distractions Age Capabilities Sensory/Visual Cognitive Physical Experience Road familiarity Impairment Training Attitudes Behaviors Speed Traffic volume One-way flow Two-way flow Control type Functional class Lane width Shoulder width Sight distance Pavement type and condition Bicyclists Distractions Enforcement Roadside Grades Curvature Signs and markings Weather Land use Pedestrians Urban Rural Time of day Light condition Scenic/interest attractions

32 Using the HFIM to Identify Potential Problems Objective: consider and document the possible road user, vehicle, and environment issues that could be contributing to confusion, errors, and crashes at the site or traffic situation that you are evaluating. Key Inputs: the basic crash or conflict data compiled in Step 1 the site visit results from Step 2a (including relevant data such as the types of vehicles, cross section dimensions, traffic volumes, speed limits, kinds of traffic control) the crash data trends from Step 2b Approach: the HFIM should include any factors and combinations of factors (interactions) that could reasonably contribute to the known or suspected opportunities for improving safety at the site under investigation. Identifying interactions will be crucial how could the individual factors in combination - create confusion, distraction, uncertainties, or misperceptions on the part of road users. 32

33 Using the HFIM to Identify Potential Problems (cont.) What is the nature of the crashes/conflicts observed? What can the most common crash types tell us about the relative contribution of road user, vehicle, and environment issues to the crashes? What are the most common contributing factors cited in the crash records? From the perspective of a road user, what might be some sources of confusion when trying to extract the most meaningful information (MMI) from the road geometry and traffic control information? How might unique issues associated with vehicle type be contributing to crashes or conflicts? Are there any unique environmental and road conditions that cause undue road user stress, additional comprehension time, or unrealistic responsive maneuvers? In general, are there any unclear or misleading cues between the roadway and user? Consider not just the factors that were present at the exact time of a crash, but also factors or events that could have occurred prior to the crash. 33

34 Partially- Completed HFIM for the Rural Multilane Example Road User Vehicle Environment Interactions Speeding behaviors Impairments due to alcohol or distraction Future increase in younger drivers Possible glare from on-coming headlamps No barriers or cables on center median No lighting High posted speed limit (75 MPH) Increased future traffic volumes due to college expansion Lack of barriers or cables across median combined with high speeds contributes to crashes and injuries due to road departures. Lack of lighting interacts with high speeds to decrease visibility of lane edges and increase perception-reaction time and likely contributes to road departures at night Relevant Sections in the HFG Speed limits may be too high for conditions, especially with a future influx of younger drivers

35 Using the HFG to Identify Potential Countermeasures (Step 3b) Objective: create a list of HFG contents corresponding to design characteristics or safety issues within the road system. Key Steps: 1. Using the Step 2 results and especially the HFIM generate a list of keywords that can be used to characterize the nature and causes of the crashes, conflicts, and related safety outcomes. 2. Review the Table of Contents and the Index in the HFG to identify Chapters, Guidelines, and Tutorials that seem broadly relevant to the HFIM interactions and underlying safety issues. 3. Examine the individual Chapters/Guidelines/Tutorials more closely to determine whether the materials in the initial list will indeed be useful for the specific site/contributing factors under consideration. 4. List the resulting Chapters, Guidelines, and Tutorials in a new column that can be added to the rightmost column of the HFIM 35

36 Using the HFG to Identify Potential Countermeasures (Step 3b) An initial review of the HFG using these keywords: medians, younger drivers, lighting, rural driving, speeding and speeding behaviors, and impaired driving (alcohol, distraction) yields the following Chapters/Guidelines as potentially relevant to this example: Chapter 6: Curves (Horizontal Alignment) 6-10 Countermeasures to Improve Pavement Delineation 6-12 Signs on Horizontal Curves Chapter 8: Tangent Sections and Roadside (Cross Section) 8-4 Overview of Driver Alertness on Long Tangent Sections Chapter 17: Speed Perception, Speed Choice, and Speed Control Speeding Countermeasures: Setting Appropriate Speed Limits Speeding Countermeasures: Communicating Appropriate Speed Limits Chapter 20: Markings 20-8 Post-mounted Delineators Chapter 21: Lighting 21-2: Countermeasures for Mitigating Headlamp Glare 21-4 Nighttime Driving

37 Completed HFIM for the Rural Multilane Example Road User Vehicle Environment Interactions Speeding behaviors Impairments due to alcohol or distraction Future increase in younger drivers Possible glare from on-coming headlamps No barriers or cables on center median No lighting High posted speed limit (75 MPH) Increased future traffic volumes due to college expansion Lack of barriers or cables across median combined with high speeds contributes to crashes and injuries due to road departures. Lack of lighting interacts with high speeds to decrease visibility of lane edges and increase perception-reaction time and likely contributes to road departures at night Speed limits may be too high for conditions, especially with a future influx of younger drivers Relevant Sections in the HFG Chapter 6: Curves (Horizontal Alignment) o 6-10 o 6-12 Chapter 8: Tangent Sections and Roadside o 8-4 Chapter 17: Speed Perception, Speed Choice, and Speed Control o 17-10, Chapter 20: Markings o 20-8 Chapter 21: Lighting o 21-2, 21-4

38 Using the HFG to Identify Potential Countermeasures (Step 3b) Key Steps (continued): 5. Go back to the individual Chapters/Guidelines/Tutorials cited in the HFIM and for each candidate guidelines being considered for application more closely examine the Design Guidelines, Discussion, and Design Issues subsections from the HFG in more detail 6. For each safety issue or risk listed in the HFIM, identify/list as appropriate: relevant road user needs, capabilities, or limitations, relevant road user perception or performance issues, specific HFG recommendations, countermeasures, or design options, and relevant data sources or research studies that could support specific design changes or enhancements. 7. Review and consider: the cross-references within the HFG and whether related guidelines beyond the initial list might contain useful information, relevant tutorials to identify useful information, trade-offs related to design and road user performance, and whether the differences between the as-built roadway and the HFG recommendations are likely to result in safety improvements. 38

39 Summary of Information in the HFG Useful to the Rural Multilane Example HFG Section Summary of Important Road User Issues and Countermeasures 6-10 Countermeasures to Improve Pavement Delineation This guideline describes how pavement markings can help driver performance. Though its focus is on curve driving, it provides useful guidance for this site. It includes guidance on edge and center lines, raised reflective pavement markers, and markers on signs Signs on Horizontal Curves 8-4 Overview of Driver Alertness on Long Tangent Sections Speeding Countermeasures: Setting Appropriate Speed Limits Speeding Countermeasures: Communicating Appropriate Speed Limits This guideline provides information on the advance placement and spacing for chevrons for curve warning signs. Designers and planners can use this information to notify the driver of the upcoming curve so that the driver can change the speed or path of the vehicle or both. Fatigue can reduce both vigilance and driver performance; fatigue is clearly a causal factor in some of the crashes at this site. This guideline explains how to break the monotony, such as adding visual complexity, or provide countermeasures, such as shoulder rumble strips and/or median barriers. This guideline discusses how to set an appropriate speed limit accounting for the unique traffic, design, and environmental aspects of a roadway. It includes standard conditions, variable speed limits, and heavy truck traffic. The PSL at this site may be too high, and a review to determine if speed is appropriately set may be helpful. This guideline discusses best practices for communicating posted speed limits to drivers and explains when to use approaches such as redundant signs, active speed warning, and in-pavement measures. There may be specific locations within this roadway segment where such countermeasures could be helpful.

40 Incorporate the HFG and the HSM into the Data-Driven Decision Making Process (3) Countermeasures from the Highway Safety Manual (HSM)

41 The Highway Safety Manual (HSM) First edition released in 2010, Updated in 2014 Three volumes covering four parts al.org/pages/default.aspx The HSM focuses on bringing quantitative safety analysis into planning design and operations. Both the predictive method and CMF Method yield outcome crash impacts (reductions or increases) for given treatments/ conditions Part A: Introduction, Human Factors, and Fundamentals Part C: Predictive Method Part B: Roadway Safety Management Part D: Crash Modification Factors

42 Tools in the HSM-Predictive Method Estimates crash frequency as a function of traffic volume and roadway geometry Equations are in HSM organized by cross-section total and injury crashes Data Requirements Roadway and location data (number of lanes, posted speed limit, etc.) Traffic volume Crash history data Local calibration factors

43 Tools in the HSM-Predictive Method Roadways currently covered by the HSM Rural two-lane, two-way roads, Rural multilane highways, Suburban arterials, and Urban arterials. Excel workbooks available to aid in calculations Refer to HSM Volume 2 for further information

44 Tools in the HSM-Crash Modification Factors (CMF) Multiplicative factor to estimate change in crash frequency associated with a treatment/countermeasure A CMF less than 1.0 indicates an expected crash reduction Effects = All Injury Crashes Data Requirements Crash history data General roadway information (location, functional class, etc.) CMF Clearinghouse (

45 Tools in the HSM-Crash Modification Factors (CMF) Applying CMFs Need to ensure the CMF matches the crash type, severity, traffic conditions, roadway type, etc. CMF s should come from high quality studies

46 Tools in the HSM-Crash Modification Factors (CMF) Applying CMFs The application of multiple treatments are determined through combination CMFs The combination CMF is calculated as follows CMF 123 = CMF 1 x CMF 2 x CMF 3 The HSM does not recommend analyzing more than three treatments at a time

47 Directing Your Questions via the Chat Pod 1. Chat pod is on left side of screen between attendees pod & closed caption pod 3. Answers will appear here unless addressed verbally 2. Type your question or comment here

48 John Campbell, Battelle Summarize the role of human factors in roadway design, operations, and safety Incorporate the HFG and the HSM into the Data-Driven Decision Making Process Illustrate how to use the HSM and the HFG together to improve decision-making 48

49 Example 3.2 Rural Multilane Highways

50 Process for Joint Use of the HSM and HFG

51 Problem Statement Problem Statement: A new campus is expected to increase traffic volume by 7,000 vehicles per day at exit 145. The DOT is evaluating the current safety of the highway south of the exit. The DOT wants to evaluate the impacts of adding lighting to the corridor and increasing the shoulder width to 10 feet. Any additional countermeasures with safety improvements will also be considered.

52 Site Characteristics Rural Principal Arterial 12-foot lanes Four-foot paved shoulder on both sides No lighting No median or roadside barriers Roadside rating of 1, open clear road sides, shallow roadside slopes 75 MPH posted speed limit Two-inch drop off between traveled way and shoulders 40-foot grass median Shoulder rumble strips to the left and the right of travel lanes in either direction No access points within 2.4-mile study segment No grade or vertical curvature Horizontal curve radius ~1,700 feet

53 Crash Data- Crashes by Severity and Year Crash Year Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) PDO Total Total Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) PDO

54 Crash Data- Crashes by Severity and Type Collision Type Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) Head-On Collision Roadway Departure Rear-end Sideswipe Same Direction Animal Total PDO Total Animal Sideswipe Same Direction Rear-end Roadway Departure Head-On Collision Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) PDO

55 Crash Data- Crashes by Severity and Contributing Factor Contributing Factors Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) Under influence of alcohol Distracted driving Cross median Following too closely Night time Exceeding speed limit Total Exceeding speed limit Night time Following too closely Cross median Distracted driving Under influence of alcohol PDO Total Fatal (K) Serious Injury (A) Evident Injury (B) Possible Injury (C) PDO

56 Conduct Human Factors Evaluation (Step 2c) Objective: review the relevant data from previous steps, and identify the individual road user, vehicle, and environment factors - and any possible interactions - that could contribute to driver or road user confusion, misperceptions, high workload, distraction, or other problems and errors. Consider key questions Relevant data points: The crash data and the description providing the details of the site provide good cues regarding possible human factors issues. In particular, the relatively high-speed limit, combined with the lack of lighting, clearly contribute to the frequent lane excursions. Moreover, the site provides little roadside safety devices once lane excursions or road departures occur - there is no cable or barrier within the central median prevent vehicles travelling in the opposite directions from crashing. Also, the presence of on-coming headlamps could lead to discomfort or disabling glare, and interfere with steering performance, leading to run off road crashes and/or head on collisions. 56

57 Some Key Questions to Ask: What is the nature of the crashes/conflicts observed? What can the most common crash types tell us about the relative contribution of road user, vehicle, and environment issues to the crashes? What are the most common contributing factors cited in the crash records? From the perspective of a road user, what might be some sources of confusion when trying to extract the most meaningful information (MMI) from the road geometry and traffic control information? How might unique issues associated with vehicle type be contributing to crashes or conflicts? Are there any unique environmental and road conditions that cause undue road user stress, additional comprehension time, or unrealistic responsive maneuvers? In general, are there any unclear or misleading cues between the roadway and user? Consider not just the factors that were present at the exact time of a crash, but also factors or events that could have occurred prior to the crash. 57

58 Partially- Completed HFIM for the Rural Multilane Example Road User Vehicle Environment Interactions Speeding behaviors Impairments due to alcohol or distraction Future increase in younger drivers Possible glare from on-coming headlamps No barriers or cables on center median No lighting High posted speed limit (75 MPH) Increased future traffic volumes due to college expansion Lack of barriers or cables across median combined with high speeds contributes to crashes and injuries due to road departures. Lack of lighting interacts with high speeds to decrease visibility of lane edges and increase perception-reaction time and likely contributes to road departures at night Relevant Sections in the HFG Speed limits may be too high for conditions, especially with a future influx of younger drivers

59 HSM Predictive Method- Base Condition Input (Step 3a) Worksheet 1A -- General Information and Input Data for Rural Multilane Roadway Segments General Information Location Information Analyst ARM Roadway SR 75 Agency or Company CS Roadway Section MP to MP Date Performed 05/17/17 Jurisdiction OH Analysis Year 2020 Input Data Base Conditions Site Conditions Roadway type (divided / undivided) Undivided Divided Length of segment, L (mi) AADT (veh/day) AA DT M AX = 89,300 (veh/day) -- 57,000 Lane width (ft) Shoulder width (ft) - right shoulder width for divided [if differ for directions of travel, use average width] 8 4 Shoulder type - right shoulder type for divided Paved Paved Median width (ft) - for divided only Side Slopes - for undivided only 1:7 or flatter Not Applicable Lighting (present/not present) Not Present Not Present Auto speed enforcement (present/not present) Not Present Not Present Calibration Factor, Cr

60 HSM Predictive Method- Proposed Condition Inputs Worksheet 1A -- General Information and Input Data for Rural Multilane Roadway Segments General Information Location Information Analyst ARM Roadway SR 75 Agency or Company CS Roadway Section MP to MP Date Performed 05/17/17 Jurisdiction OH Analysis Year 2020 Input Data Base Conditions Site Conditions Roadway type (divided / undivided) Undivided Divided Length of segment, L (mi) AADT (veh/day) AADT MAX = 89,300 (veh/day) -- 64,000 Lane width (ft) Shoulder width (ft) - right shoulder width for divided [if differ for directions of travel, use average width] 8 10 Shoulder type - right shoulder type for divided Paved Paved Median width (ft) - for divided only Side Slopes - for undivided only 1:7 or flatter Not Applicable Lighting (present/not present) Not Present Present Auto speed enforcement (present/not present) Not Present Not Present Calibration Factor, Cr

61 HSM Predictive Method- Results Comparison Base Condition Results (1) (2) (3) (4) Crash severity level Roadway Predicted average crash frequency (crashes/year) segment length (mi) Crash rate (crashes/mi/year) Total Fatal and Injury (FI) Fatal and Injury (FI a ) Property Damage Only (PDO) NOTE: Using the KABCO scale, these include only KAB crashes. Crashes with severity level C (possible injury) are not included. Proposed Condition Results (1) (2) (3) (4) Crash severity level Roadway Predicted average crash frequency (crashes/year) segment length (mi) Crash rate (crashes/mi/year) Total Fatal and Injury (FI) Fatal and Injury (FI a ) Property Damage Only (PDO) NOTE: Using the KABCO scale, these include only KAB crashes. Crashes with severity level C (possible injury) are not included.

62 HSM CMF Method- Countermeasures Selected Cable Median Barrier Steel Median Barrier Provide Lighting Install Safety Edge Increase Shoulder Width Cable Median Barrier AND Increase Shoulder width

63 HSM CMF Method- Results CMF Cable Median Barrier Steel Median Barrier Provide Lighting Install Safety edge Increase Shoulder Width from 4ft to 12 ft. Cable Median Barrier and Increase Shoulder Width CMF Crash Type Applicable Site Crashes CMF Cross Median Standard Error CMF Estimated Crash Impacts High Low High Low All cross median injury crashes (K,A,B,C) All cross median injury crashes (K,A,B,C) Nighttime Nighttime injury crashes (K,A,B,C) Roadway Departure All roadway departure crashes Roadway Departure and Head-On Injury Crashes (K,A,B,C) Combined Treatment Countermeasures All cross median, Injury Crashes (K,A,B,C)

64 Using the HFG to Identify Potential Countermeasures (Step 3b) An initial review of the HFG using these keywords: medians, younger drivers, lighting, rural driving, speeding and speeding behaviors, and impaired driving (alcohol, distraction) yields the following Chapters/Guidelines as potentially relevant to this example: Chapter 6: Curves (Horizontal Alignment) 6-10 Countermeasures to Improve Pavement Delineation 6-12 Signs on Horizontal Curves Chapter 8: Tangent Sections and Roadside (Cross Section) 8-4 Overview of Driver Alertness on Long Tangent Sections Chapter 17: Speed Perception, Speed Choice, and Speed Control Speeding Countermeasures: Setting Appropriate Speed Limits Speeding Countermeasures: Communicating Appropriate Speed Limits Chapter 20: Markings 20-8 Post-mounted Delineators Chapter 21: Lighting 21-2: Countermeasures for Mitigating Headlamp Glare 21-4 Nighttime Driving

65 Completed HFIM for the Rural Multilane Example Road User Vehicle Environment Interactions Speeding behaviors Impairments due to alcohol or distraction Future increase in younger drivers Possible glare from on-coming headlamps No barriers or cables on center median No lighting High posted speed limit (75 MPH) Increased future traffic volumes due to college expansion Lack of barriers or cables across median combined with high speeds contributes to crashes and injuries due to road departures. Lack of lighting interacts with high speeds to decrease visibility of lane edges and increase perception-reaction time and likely contributes to road departures at night Speed limits may be too high for conditions, especially with a future influx of younger drivers Relevant Sections in the HFG Chapter 6: Curves (Horizontal Alignment) o 6-10 o 6-12 Chapter 8: Tangent Sections and Roadside o 8-4 Chapter 17: Speed Perception, Speed Choice, and Speed Control o 17-10, Chapter 20: Markings o 20-8 Chapter 21: Lighting o 21-2, 21-4

66 Summary of Information in the HFG Useful to the Rural Multilane Example HFG Section Summary of Important Road User Issues and Countermeasures 6-10 Countermeasures to Improve Pavement Delineation This guideline describes how pavement markings can help driver performance. Though its focus is on curve driving, it provides useful guidance for this site. It includes guidance on edge and center lines, raised reflective pavement markers, and markers on signs Signs on Horizontal Curves 8-4 Overview of Driver Alertness on Long Tangent Sections Speeding Countermeasures: Setting Appropriate Speed Limits Speeding Countermeasures: Communicating Appropriate Speed Limits This guideline provides information on the advance placement and spacing for chevrons for curve warning signs. Designers and planners can use this information to notify the driver of the upcoming curve so that the driver can change the speed or path of the vehicle or both. Fatigue can reduce both vigilance and driver performance; fatigue is clearly a causal factor in some of the crashes at this site. This guideline explains how to break the monotony, such as adding visual complexity, or provide countermeasures, such as shoulder rumble strips and/or median barriers. This guideline discusses how to set an appropriate speed limit accounting for the unique traffic, design, and environmental aspects of a roadway. It includes standard conditions, variable speed limits, and heavy truck traffic. The PSL at this site may be too high, and a review to determine if speed is appropriately set may be helpful. This guideline discusses best practices for communicating posted speed limits to drivers and explains when to use approaches such as redundant signs, active speed warning, and in-pavement measures. There may be specific locations within this roadway segment where such countermeasures could be helpful.

67 Develop and Prioritize Countermeasures (Step 4) Potential Source Discussion Countermeasure or Solution Install highway lighting Install cable median barrier HSM HSM & HFG, 8-4 The HSM indicates high confidence in this solution This is an obvious solution and is well-supported by the HSM analysis. This is an either or solution with respect to the steel median (below); only one of these solutions should be selected. Install steel median barrier HSM & HFG, 8-4 This is an obvious solution and is well-supported by the HSM analysis. This is an either or solution with respect to the cable median (above); only one of these solutions should be selected. Widen shoulders HSM Only feasible during a repaving project; also, the safety benefits Install cable median barrier and Widen shoulders HSM & HFG, 8-4 are uncertain. This combined treatment solution would represent a situation where the cable median barriers are being installed during a repaving project. This scenario encompasses the benefits of the cable median barrier installation along with the opportunity for widening shoulders. Install safety edge HSM While feasible, the safety benefits of this solution are uncertain. However, the HFG (6-10) suggests a similar solution and may provide useful information. Consider markings to improve delineation Consider other countermeasures to address run off road crashes. Set and communicate speed limits to improve safety Add post-mounted Delineators HFG, 6-10 HFG, 6-12, 8-4 HFG, & HFG, 20-8 A number of solutions are presented in this guideline; it also provides additional detail on edge lines that may compliment the HSM recommendation for safety edges. Other countermeasures in addition to the median barriers noted above, could be considered (such as curve warning signs) The posted speed limit should be evaluated, and countermeasures for effectively communicating the speed limit to drivers considered for implementation If drivers are unclear about the roadway alignment, post-mounted delineators may help them maintain safe lane positions. Countermeasures to improve nighttime driving. HFG, 21-2 & 21-4 To improve visibility at night and reduce nighttime crashes, a range of countermeasures (e.g., glare screens, advance warning signs, additional lighting) could be implemented.

68 Conduct Safety Assessment (Step 5) After the installation any individual or combination of treatments, it is necessary to conduct a safety effectiveness evaluation. By conducting the evaluation, similar projects may be implemented or rejected within the same jurisdiction. For more information on safety effectiveness evaluations refer to: The Crash Modification Factor Clearinghouse recommendations for developing CMFs. Observational Before-After Studies in Road Safety, E. Hauer, 1997.

69 Directing Your Questions via the Chat Pod 1. Chat pod is on left side of screen between attendees pod & closed caption pod 3. Answers will appear here unless addressed verbally 2. Type your question or comment here

70 Resources 2 nd Edition of the Human Factors Guidelines for Road Systems cond.pdf Highway Safety Manual Crash Modification Factor Clearinghouse HFG/HSM Primer To be released by NCHRP soon Safety Center will send an to webinar participants when released 70

71 Learning Outcomes In this webinar, you have learned to: Summarize the role of human factors in roadway design, operations, and safety? Incorporate the HFG and the HSM into the Data-Driven Decision Making Process Illustrate how to use the HSM and the HFG together to improve decision-making 71

72 Upcoming 2018 Webinars Creating a Rural Transportation Planning Organization Tues. March 20, 11:00 AM 12:30 PM Mountain Sharing the Road with Slow Moving Vehicles Thurs. April 26, 11:00 AM 12:30 PM Mountain Archived Webinars Access the webinar archives 72

73 Contact Information If you have any questions related to this presentation, please contact: John Campbell - campbellj@battelle.org Or contact the National Center for Rural Road Safety Help Desk at: (844) or info@ruralsafetycenter.org 73