DEVELOPMENT OF HUMAN FACTORS DESIGN GUIDELINES John Campbell

DEVELOPMENT OF HUMAN FACTORS DESIGN GUIDELINES John Campbell October 24, 2007 1

Introductions Presenter, John L. Campbell • Research Leader, Battelle Human Factors Transportation Center • 22 years of experience in the development of transportation systems and human factors design guidelines. • 1985 to 1991, conducted research and developed design guidelines for advanced automotive displays for Hughes Aircraft Company’s Display Systems and Simulation Laboratory. • 1991 to 1994, led the conduct of human factors research projects at Anacapa Sciences, with particular emphasis on advancing human factors methodology for development of design guidelines and applying these advances to the development of automotive displays, icons, symbols, and secondary controls. • Since joining Battelle in 1994, has had primary responsibilities for design guideline development and transportation research projects in the areas of Crash Avoidance Systems (CAS), Advanced Traveler Information Systems (ATIS), Icons, Intelligent Transportation Systems, and Driver modeling. 2

Introductions Presenter, John L. Campbell (cont. ) • Past guideline development efforts include: – Human factors guidelines for road systems (TRB, 2007) – Human factors lessons learned for crash warning systems (NHTSA, 2006) – A CD-ROM-based interactive software tool for symbol design, Icon IDEA (Icon Development and Evaluation Assistant; FHWA, 2003) – Human factors guidelines for in-vehicle icons (FHWA, 2002) – Human factors design guidelines for in-vehicle navigation systems (FHWA, 1999) – Interface guidelines for intersection collision avoidance devices (NHTSA, 1997) 3

Discussion Topics • Developing Human Factors Guidelines • Examples of Past Guidelines • Lessons Learned 4

Developing Human Factors Guidelines Role of Guidelines Original Research Compilations EXPERIMENTS Journal Articles Conference Proceedings Books Literature Reviews Handbooks Technical Reports User-Centered Guidelines System Designer needs for content, organization, and format Design Environment Formulation of Individual Guidelines • Objectives & Tasks • • • Available Design Dat Design Process Existing Constraints “Givens” in Design Diverse Designers Standards Database of Human Factors Research Integrative review of data sources FINAL DESIGN SPECIFICATIONS 5

Developing Human Factors Guidelines Historical Perspective • Despite increasing demands for HF design guidance, it has been difficult for the HF community to develop information that designers judge to be valuable. – designers didn’t use and had little interest in available HF information (Meister & Farr, 1967). – designers found much of the HF research literature difficult to understand that few data were generalizable to specific issues of concern (Rouse & Cody, 1988) – designers rated information as very costly to obtain, with low value; they, would only expend small amounts of effort to obtain the information (Burns & Vicente, 1994) – general design principles and HF heuristics were not deemed useful by non-human factors designers (Campbell, Carney, & Kantowitz, 1997) 6

Developing Human Factors Guidelines Key Challenges • Identifying appropriate content for the guidelines • Lack of generalizeable research data • Developing selection criteria for choosing data sources to be used to produce guidelines • Variability across guideline users • Developing effective guidelines without restricting innovative and effective design 7

Developing Human Factors Guidelines Key Assumptions • System design will proceed with or without human factors inputs to the design process. • The “best-available” human factors information is better than no HF information at all. • Users should be able to determine the relative contribution of expert judgment and experience data in design guidelines. • HF design guidelines are intended to augment, not replace, designer experience, skill, and judgment. 8

Developing Human Factors Guidelines Key Steps 9

Developing Human Factors Guidelines Step 1: Conduct User Requirements Analysis n n n n Demographics (education, work experience) Primary Design Responsibilities Design process Current HF Inputs to design Difficulties in acquiring or using HF design information (and suggested solutions) Priorities for system functions Priorities for HF topics and design data Review of candidate guideline formats 10

Developing Human Factors Guidelines Step 2: Identify Relevant Components of the Design Process • Key steps • Starting points or “givens” in their design effort • Manner in which requirements are expressed • Design constraints • Relative priorities among potential topics 11

Developing Human Factors Guidelines Step 3: Select Data Sources • Acquire a comprehensive and representative data base of relevant sources • Employ a broad, inclusive search strategy • Sources obtained from: – in-house libraries – university collections – on-line data bases, NTIS, DTIC, DIALOG, SAE – foreign collections 12

Developing Human Factors Guidelines Step 4: Determine the Quality and Applicability of Data Sources • Criteria include: – source type – intended application area – for empirical sources: - study setting - independent and dependent variables - sampling approach - internal and external validity – consistency of findings/recommendations to other sources 13

Developing Human Factors Guidelines Step 5: Formulate the Design Guideline • Conduct integrative review and analysis of data sources • Consider the design constraints and uncertainties associated with specific guideline topics • Consider the use of transformed data • Identify any caveats, exceptions, interactions with other guidelines, special performance issues 14

Developing Human Factors Guidelines Process for Recent Road System Guidelines 15

Developing Human Factors Guidelines Presentation Format Abbreviated Chapter Title Revision Handbook Title Guideline Title Version Bar Scale Rating (Both Pages) Introduction (Both Pages) Discussion Design Guideline Design Issues Figure, Table, or Graphic Cross References Left-hand page Page Numbers Right-hand page 16

Examples Icon Guidelines for the FHWA Use of Text Labels in Icon Design Ineffective Use of Text Label Make the type >0. 27 degrees visual angle. Avoid using italics to emphasize words. Overheight vehicles take another route around restricted clearance. The space between lines should be at least 1/30 the line length. Effective Use of Text Label Use both uppercase and lowercase letters. Use a clear and simple font. Low Clearance Ahead Keep text labels brief - use no more than 2 to 3 words. 17

Examples Icon Guidelines for the FHWA Perceptual Principles for Icon Design 18

Examples Icon Guidelines for the FHWA Identifying Icons as Part of a Group 19

Examples CWS “Lessons Learned” for NHTSA Selecting Display Types for FCW Devices Display Type Explanation Example Analog Display Provides a graphical representation of continuous information. Scale-based FCW Discrete Display Provides binary on/off information. “Vehicle detected” status indicator Digital Display Information is presented directly as a number. Headway distance display (in meters) Alphanumeric Display Information is presented as messages in full or abbreviated form. Complex system error message Symbol/Icon Simple graphic signs that transmit message information. Note that some simple and familiar alphanumeric displays (e. g. , Stop!; Brake!) may function as symbols. FCW Icon 20

Examples CWS “Lessons Learned” for NHTSA Recommended Detection Zones for LCW Devices 21

Examples CWS “Lessons Learned” for NHTSA Design of CWS Controls A. Well-designed Control Placement B. Poorly-designed Control Placement Controls are aligned with forward view Controls are within fingertip reach Higher priority controls are on the outside (easier to manipulate) Controls can be activated with both hands on the wheel Controls are coded by location for easy identification Adapted from Reference 6 Controls are not aligned with the forward view (driver must look away and down to see controls and display) Placement requires increased glance time Controls are partially obscured by steering wheel Driver must reach to operate control Controls are poorly or not labeled Inappropriate control type for on/off switch 22

Examples HF Guidelines for Road Systems (TRB/NCHRP) Schematic showing the Perception-Reaction Time and Maneuver Time Components of Sight Distance 23

Examples HF Guidelines for Road Systems (TRB/NCHRP) Acceptable Gap Distance 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 24

Examples HF Guidelines for Road Systems (TRB/NCHRP) Countermeasures for Improving Accessibility of Vision-impaired Pedestrians at Roundabouts 25

Lessons Learned • Involving end-users in the guideline development and review process is crucial to success. • Human factors design guidelines based on the "best-available" human factors research data can still provide useful information to designers. • The human factors discipline has the tools needed to provide clear, relevant, and useful design guidelines to the system design community. 26