1. Enhancing Highway Safety: Applications of the Human Factors Guidelines (HFG) for Road Systems Presentation to the 2015 Annual Meeting of the Western Association of State Highway and Transportation Officials (WASHTO)
John L. Campbell, Ph.D. Battelle, Center for Human Performance and Safety
July 20, 2015

2. Discussion Topics
Background to the Human Factors Guidelines (HFG) for Road Systems
Example Guidelines from the HFG
Applications of the HFG
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3. History and Status of the HFG Effort
The purpose of the HFG is to provide the best factual information and insight on road users’ characteristics to facilitate safe design and operational decisions.
Development of the HFG has been an ongoing project since 2001.
3 subsections (NCHRP 600 A, B, & C) of the HFG were published in 2007, 2009, & 2010.
2nd Edition of the full HFG was published in 2012.
90 distinct guideline topics
475+ references
PDF version with updated external and internal links
2-hour training course
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4. Specific Requirements for the HFG
Focus on road user needs, limitations, and capabilities
Reflect end-user requirements for content, format, and organization (clear, relevant, and easy-to-use )
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
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5. Presentation Format Used in the HFG
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6. Example Guidelines from the HFG
Acceptable Gap Distance (from Chapter 10)
Time Gap (tg) (seconds) at design speed of major road
Design Vehicle
Left Turn
Right Turn
Passenger car
7.5
6.5
Single-unit truck
9.5
8.5
Combination truck
11.5
10.5

7. Example Guidelines from the HFG
Countermeasures for Improving Accessibility of Vision-impaired Pedestrians at Roundabouts (From Chapter 10)

8. Example Guidelines from the HFG
Driver Comprehension of Signs (from Chapter 18)
Format
Example
Guideline
Text Only
Use for highly complex messages
Use when indicating hazards
Use for destination information
Use in areas requiring frequent lane shifts
Graphic / Icon Only
Use for safety and warning information
Use for prohibited actions
Use in visually degraded conditions
Use in areas with higher posted speeds
Use diagrammatic graphics when road geometry violates the drivers’ expectations
Minimize symbol complexity by using few details
Mixed
Add text when symbols alone are unintuitive
Keep text to no more than two-three words
Use a clear and simple font for the text

9. Ways to Use the HFG
Enhance initial roadway planning and design activities
Conduct diagnostic assessments of safety concerns & incidents
Support road safety audits
Identify & select safety countermeasures
Educate traffic engineers & designers on user needs, capabilities, and limitations
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10. Applications of the HFG
From , 5 State DOTs participated as test sites to implement the HFG and assess its value.
Arizona: As part of 7 rural and urban RSAs.
Delaware: Day-to-day use and to diagnose specific trouble spots.
Idaho: As part of a new “Highway Corridor Safety Analysis Project” to help prioritize safety improvement needs and projects across the state.
Nevada: To assist 4 RSAs and annual reviews of high-crash sites involving intersections.
Wisconsin: To support 2 RSAs: an urban planning-level engineering analysis, and a rural high-crash location.
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11. Applications of the HFG
A new Human Factors training course from NHI.
Develop a training course based on the Human Factors Guidelines (HFG) for Roadway Systems (NCHRP Report 600).
The workshop will assist practitioners in identifying the value of human factors in operations and design, and demonstrate how to apply human factors in practice.
Specific Goals 
Describe human factors as they apply to road systems.
Describe how the HFG relates to existing standards and manuals (e.g., HSM, MUTCD, and AASHTO’s Policy on Geometric Design of Highways and Streets).
Apply the HFG to case studies (new project designs, improvement designs, and countermeasures).
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12. For More Information…
2nd Edition of the full HFG; NCHRP Report 600 available at:
John L. Campbell, Battelle
Mark S. Bush, TRB/NCHRP
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