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Publication Number: FHWA-RD-96-177
Date: October 1997

Development of Human Factors Guidelines for Advanced Traveler Information Systems and Commercial Vehicle Operations: Definition and Prioritization of Research Studies

 

1. INTRODUCTION

 

GOALS

STUDIES/ISSUES

RATING CRITERIA

 

GOALS

The activities documented in this report were conducted in Task I of this effort. The major goal of this Task was to produce a prioritized list of candidate studies and issues. Figure 1 shows the three steps taken to reach this goal. First, issues were compiled from earlier research based upon working papers for Tasks A through H. Table 1 lists the reports prepared for the Federal Highway Administration (FHWA). Second, a set of criteria are defined for evaluating the list of issues. Third, a linear psychometric model is used to prioritize this list and a brief validation study is conducted to ensure that the method used to generate the prioritized list was effective.

Figure 1. Flowchart of Task I subtasks
Figure 1. Flowchart of Task I subtasks

 

Table 1. Summary of working papers.

TASK TITLE AUTHORS
A CONDUCT AN ATIS/CVO RELATED LITERATURE REVIEW WORKING PAPER Thomas Dingus
Melissa Hulse Janice Alves-Foss Scott Conger Steven Jahns
Andrew Rice
Ian Roberts Richard Hanowski
Douglas Sorenson
B IDENTIFY ADVANCED TRAVELER INFORMATION SYSTEM (ATIS) AND COMMERCIAL VEHICLE OPERATIONS (CVO) SYSTEM OBJECTIVES AND PERFORMANCE REQUIREMENTS WORKING PAPER Marvin McCallum John Lee Thomas Sanquist William Wheeler
C DEFINE ATIS/CVO FUNCTIONS WORKING PAPER John Lee
Jennifer Morgan Melissa Hulse
William Wheeler Tom Dingus
D PERFORM A COMPARABLE SYSTEMS ANALYSIS DRAFT WORKING PAPER David Clarke Michael McCauley Thomas Dingus Thomas Sharkey John Lee
E PERFORM TASK ANALYSIS SUMMARY WORKING PAPER William Wheeler John Lee
Mireille Raby
Rhonda Kinghorn Alvah Bittner Marvin McCallum
F IDENTIFY ATIS/CVO USERS AND THEIR INFORMATION REQUIREMENTS WORKING PAPER Woodrow Barfield Alvah Bittner
Neil Charness Martha Hanley Rhonda Kinghorn
Francine Landau John Lee
Fred Mannering Linda Ng
William Wheeler
G IDENTIFY STRENGTHS/WEAKNESSES OF ALTERNATE INFORMATION DISPLAY FORMATS WORKING PAPER Melissa Hulse Thomas Dingus Michael Mollenhauer
Brian McKinney
Yung-Ching Liu Steven Jahns Timothy Brown
H IDENTIFY AND EXPLORE DRIVER ACCEPTANCE OF IN-VEHICLE ITS (INTELLIGENT TRANSPORTATION SYSTEMS) SUMMARY WORKING PAPER Barry Kantowitz John Lee
Curtis Becker
Alvah Bittner
Susan Kantowitz
Richard Hanowski
Rhonda Kinghorn
Michael McCauley Thomas Sharkey Marvin McCallum
S. Todd Barlow

 

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STUDIES/ISSUES

Table 2 lists candidate studies and issues in 11 categories labeled A through K:

  • Coordination of multiple ATIS functions.
  • Driver function and information requirements.
  • Reliability, timing, and priority of information.
  • Interface form and modality.
  • Timesharing, attention, and workload.
  • Effect of ATIS on driving performance.
  • Driver acceptance.
  • Navigation and route selection strategies.
  • Training and education.
  • Design and presentation of human factors design guidelines.
  • Research strategies and methods.

These issues have all been drawn from working papers for Tasks A through H.

Table 2. Rated studies/issues.

LABEL STUDY/ISSUE
  COORDINATION OF MULTIPLE ATIS FUNCTIONS
A1 Examine the cognitive demands placed on the driver by the need to transition from one ATIS function to another.
A2 Examine the physical demands placed on the driver by the need to transition from one ATIS function to another.
A3 Observe actual driving behavior to reveal the need to integrate functions in ways that were not identified in the analytic approach. These observations should not be bound by current ATIS technology.
A4 Identify how complex interactions among ATIS functions might affect driver understanding and response to the system.
A5 Examine the workload implications of requiring drivers to transform and enter information into the system.
A6 Examine the driver acceptance implications of requiring drivers to transform and enter information into the system.
A7 Examine the effect on driver performance of integrating non-ATIS/CVO equipment (radar/laser detectors, laptop computers, cellular phones) with ATIS equipment.
A8 Examine how to support sharing information (e.g., status, location, availability of resources) among dispatches to ensure effective decision making.
  DRIVER FUNCTION AND INFORMATION REQUIREMENTS
B1 Identify how specific information needs vary as a function of driver characteristics (e.g., age, gender, etc.).
B2 Identify information drivers need and want from In-vehicle Signing Information Systems (ISIS) and In-vehicle Safety Advisory and Warning Systems (IVSAWS).
B3 Identify how the information drivers need and want from road sign (ISIS) and warning systems (IVSAWS) might influence behavior.
B4 Identify what types of ATIS information should be displayed to drivers automatically.
B5 Identify what types of ATIS information should be available upon request.
B6 Describe the specific information needs/wants of CVO drivers for various situations, such as local versus long distance, urban views. rural, and emergency response versus commercial.
  RELIABILITY, TIMING, AND PRIORITY OF INFORMATION
C1 Identify how priorities specific to CVO information compare to other ATIS information.
C2 Investigate how best to support driver performance when the ATIS fails due to unreliable global positioning system (GPS) signals or other anomalous circumstances.
C3 Identify how ATIS information prioritization can enhance driving performance and response to ATIS information.
C4 Examine how information reliability (e.g., false alarms) influences driver adaptation and enhance the potential for an improper response to ISIS/IVSAWS.
C5 Investigate how to display multiple ISIS and IVSAWS messages so that drivers can identify relevant information and react appropriately.
C6 Examine how the timing of ISIS and IVSAWS information, with respect to the location of the incident, influences driver reaction to the information.
C7 Identify how and when information related to weather conditions and availability of specialized fuel and services should be provided to CVO drivers.
C8 Since commercial vehicles have limited maneuverability, identify the most effective type and timing of information to present to CVO drivers.
C9 Examine how the reliability and priority of regulatory information affect CVO driver workload.
  INTERFACE FORM AND MODALITY
D1 Identify the performance implications of inconsistent display formats across ATIS subsystems.
D2 Identify features that will benefit/require standardization across many types of ATIS systems and functions.
D3 Identify how display characteristics, such as modality, influence driver comprehension of advisory system information.
D4 Examine the performance differences associated with focusing all ISIS and IVSAWS information through either single or multiple display channels.
D5 Evaluate how input device characteristics might need to vary across subsystems.
D6 Evaluate driver perception and control characteristics such as hand-finger coordination and touch accuracy that might influence ATIS design.
D7 Examine the effect of display form (e.g., text versus graphic) on driver decision making and problem solving during route planning and selection.
D8 Examine how the interface form (e.g., text versus graphic, touch screen versus steering wheel controls) should change from pre–drive to drive and park modes.
D9 Evaluate the types of information suitable for a HUD display.
D10 Determine how interface form and modality influences driver interpretation of ISIS and IVSAWS features.
D11 Generate rules to pair types of information with display modality, for individual displays and for combinations of displays.
D12 Evaluate the effectiveness of multimodality displays, such as voice in combination with text.
D13 Identify the relationship between icon characteristics and information types that maximize icon effectiveness and salience.
D14 Identify how message length and wording for voice-based interfaces affect driving performance and message comprehension.
D15 Determine what factors influence synthesized voice message intelligibility.
D16 Assess how the fatigue that plagues CVO drivers (e.g., 8 to 12 h shift) might interact with complex in–vehicle systems to degrade driver performance.
D17 Identify specific concerns regarding how display formats and modality impact CVO driver workload.
D18 Identify the display design characteristics required to support ATIS/CVO systems in large, noisy, and vibration prone commercial vehicles.
D19 Examine how to display information such as "weight–in–motion" to promote regulatory compliance, especially if the information is different than expected.
D20 Examine how information can be displayed to dispatchers to support the complex decision–making process associated with allocation of emergency response crews.
D21 Examine how display design might aid the dynamic allocation of driver visual and cognitive resources.
  TIME SHARING, ATTENTION, AND WORKLOAD
E1 Identify a subset of environmental factors that interacts with ATIS to influence driver workload levels.
E2 Evaluate how different types of information, displayed using a HUD, affect cognitive attention devoted to the roadway.
E3 Examine the limits of visual and cognitive attention concerned with receiving information from ATIS when driving.
E4 Identify which functions to "lock out" during in–transit and provide only during zero–speed and pre–drive conditions.
E5 Identify ATIS functions a driver might need or want to use during the various driving activities, such as driving, parking, and stopping.
E6 Examine whether availability of information and functions should depend on individual differences such as age, gender, and experience.
E7 Identify the allowable functions of ATIS/CVO systems under conditions of driver impairment.
E8 Identify how ATIS information flow might be managed to capitalize on the dynamic nature of driver workload.
E9 Identify how estimates of real–time driver workload can be used to avoid overload by moderating information from ATIS.
E10 Identify the compensatory actions drivers take to moderate their workload, and how ATIS/CVO systems might affect those actions.
E11 Identify how the dynamic characteristics of driver workload interact with the form of the ATIS interface.
E12 Examine the requirements to support the complex onboard data management requirements that commercial vehicle drivers experience.
E13 Identify potential for overload of specialized CVO drivers such as emergency vehicle operators.
E14 Examine how in–vehicle road sign information (e.g., ISIS) affects workload especially under nighttime, poor weather, and other reduced visibility conditions.
  EFFECT OF ATIS ON DRIVING PERFORMANCE
F1 Examine how attention to different types of ATIS information influences the primary task of driving.
F2 Examine how route guidance systems might adversely influence driver detection and recognition of unusual roadway events.
F3 Determine whether drivers' reliance upon navigational cues outside the vehicle influence their observation of external hazards, compared to when they rely on navigational cues presented by an ATIS.
F4 Identify factors that may influence drivers to defer to the "Expert System" and fail to recognize a hazard when one is present.
F5 Examine how to display CVO-specific highway safety information (e.g., bridge clearance, width, and restrictions) with minimum interference in attention to the roadway.
  DRIVER ACCEPTANCE
G1 Evaluate the effect of information reliability and inaccuracies on driver acceptance and use of ATIS/CVO systems.
G2 Evaluate driver acceptance of "lock–out" designs that only allow driver to access functions under certain circumstances.
G3 Evaluate how driver acceptance may decline when the driver is forced to interact with multiple subsystems, particularly when this interaction is exacerbated by demanding road conditions.
G4 Investigate factors that influence acceptance of non-verbal and verbal alerts and messages, such as repeat cycle frequency.
G5 Evaluate acceptability of different types of In–Vehicle Routing and Navigation Systems maps, symbols, and icons.
G6 Investigate the effect of dynamic route scheduling on the perceived quality of worklife and corresponding driver acceptance.
G7 Examine the effectiveness of destination approach guidance for CVO in a congested, reduced sight distance, and increased pedestrian traffic environment.
G8 Determine whether CVO drivers will accept a "lock–out" design which limits access to all or selected functions while moving.
G9 Determine how learning about ITS systems and increased experience with them over time affects acceptance of ATIS/CVO.
G10 Examine how the accuracy of information pertaining to availability and current deployment of resources affects dispatcher acceptance and interaction with the system.
  NAVIGATION AND ROUTE SELECTION STRATEGIES
H1 Investigate how ATIS interface designs and parameters of routing algorithms (e.g., optimize for safety, time, distance) affect route acceptability.
H2 Investigate factors that influence driver's perception of the effectiveness of automatic routing.
H3 Investigate information requirements associated with driver "way–finding" and destination selection strategies.
H4 Evaluate the effect of destination–focusing navigational strategies on driver stress and driver acceptance.
H5 Determine the information content of maps to support different ATIS/CVO functions.
  TRAINING AND EDUCATION
I1 Determine system characteristics that eliminate or minimize training needs.
I2 Examine how training might enhance driver acceptance of routing suggestions.
I3 Identify what training techniques could be incorporated into the operation of the different subsystems.
I4 Examine how best to develop videotape–based training to illustrate ATIS functions.
I5 Examine the cost/benefit trade–off associated with training CVO drivers to accommodate more ATIS information.
  DESIGN AND PRESENTATION OF HUMAN FACTORS DESIGN GUIDELINES
J1 Investigate how to structure design guidelines to help designers address human factors issues in ATIS designs which support the needs of the driver.
J2 Investigate alternate guideline presentation formats (e.g., expert systems, electronic data base, standard data base) so as to be compatible with designer needs.
J3 Investigate the design process to identify designer needs for guideline content and format.
  RESEARCH STRATEGIES AND METHODS
K1 Generate multivariate constructs to measure driver capacity and workload.
K2 Identify measures comprehensive enough to allow metacomparisons with existing research.
K3 With mass market penetration, identify methods to evaluate and predict consequences of ATIS/CVO system use.
K4 Develop methods to link driver performance to more global measures of system performance, such as specified by the ITS goals.
K5 Develop a set of consistent subjective measures across experiments so that rating scales are common across experiments.

 

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RATING CRITERIA

Table 3 lists rating criteria drawn from three broad categories. The first set of criteria are the five categories used in the ITS America Strategic Plan; these were discussed in detail in the Task B working paper. From a human factors perspective, it seems that Safety would be the most important of these 5; indeed, ITS America places human factors in a Safety and Human Factors committee. This hypothesis will be evaluated in the following Results section of this report. Four other important criteria follow in table 3. Existing Data refers to the presence in the human factors literature of empirical results that apply directly to ITS design guidelines. There is no need to duplicate existing efforts; project resources are best saved for areas where there are no existing data. Guidelines refers to the applicability of issues to the major end product of this entire research project. While the Task F working paper found many guidelines, they were not suitable for direct application to ATIS/CVO. Older Drivers refers to the specific applicability of issues to the population of aging drivers. A special concern for this population has been mandated by FHWA. Younger Drivers refers to the opposite end of the driving continuum. While this population, although most at risk, is not specifically mandated as an object of study, it might be worthwhile to include it as a criterion to be contrasted against the Older Driver criterion. For example, an issue that scored high on the Older Driver criterion might be viewed differently depending upon its score for the Younger Driver. Issues scoring high on the Older Driver criterion but low on the Younger Driver criterion would be more salient than issues scoring high on both Older and Younger Driver criteria.

Table 3. Rating criteria.

ITS AMERICA CRITERIA RATINGS FIELD METHODOLOGY
Congestion
Safety
Mobility
Environment
Economic
Cost
Time
Practicality
Generality
Suitability
OTHER CRITERIA RATINGS SURVEY METHODOLOGY
Existing Data
Guidelines
Older Drivers
Younger Drivers
Cost
Time
Practicality
Generality
Suitability
LABORATORY METHODOLOGY
Cost
Time
Practicality
Generality
Suitability

 

The last five criteria are related to methodology. Three general methodologies are considered: laboratory (including simulators), field studies (on the road), and surveys. For each methodology all five criteria were rated.

Table 4 contains the precise definition of each criterion given to the raters. These definitions were provided in writing to all raters.

Table 4. Criterion definition.

CRITERIA DEFINITION
Congestion Decreased traffic congestion has been identified as the primary goal of ITS. Major benefits include better use of roadway capacity by shifting traffic from congested roadways to routes with excess capacity. Benefits to both private and commercial vehicle operators are seen as directly related to reduced travel time. Decreased traffic congestion may result from a variety of ATIS functions including those that provide travelers with information regarding alternative modes of transportation, such as bus, rail, air, and ride–sharing. Issues directly related to reducing congestion will be more critical.
Safety ITS technology is seen as providing an opportunity to improve safety by reducing crashes, contrasted with the traditional approach of increasing " crash worthiness." The basic strategies identified for improving safety center around avoiding areas of congestion, being warned of hazards, reducing levels of congestion (that are associated with a higher incidence of accidents). Another possible positive aspect of ATIS would be the reduction in frequency of drivers simultaneously holding a map while driving a vehicle. ATIS may also jeopardize safety. Specifically, concerns include erroneously directing drivers down one–way streets the wrong direction, reducing the time spent by drivers monitoring the roadway, and reducing reaction time to unanticipated hazards due to high levels of mental workload. Issues closely related to driver safety will be more critical.
Mobility The objective of increased and higher quality mobility is used to refer to a broad range of associated performance requirements that address the traveler's well being, comfort, enjoyment, and access to travel. Well being, comfort, and enjoyment requirements range from reducing the general level of stress while driving to increasing access to scenic and recreation areas. Access to travel requirements include both improved automobile access, as well as improved access to alternative modes of travel. Finally, this objective is commonly referred to when noting the requirement to increase the mobility of the elderly, disabled, and economically disadvantaged segments of the population. Critical issues will directly relate to enhanced mobility.
Environment The objective of environmental quality includes improved energy efficiency and other benefits such as reduced noise pollution, reduced travel, and shifts in the mode of travel. Improved environmental quality and energy efficiency will be accomplished by decreasing traffic congestion, diverting travelers from single–occupancy vehicles, accommodating smoother more evenly distributed traffic flow, reducing travel time, and demand management based on road pricing. Issues closely related to furthering the environment should be rated highly.
Economic The objective of improved economic productivity has consequences for both commercial and private drivers. From the institutional perspective, this objective can be achieved by reducing total institutional expenditures for the transportation infrastructure. From the individual and CVO perspective, improved economic productivity relates to specific gains by individuals and commercial operators. A closely–related objective is improved energy consumption, which translates into cost savings for all components of the economy. Issues closely related to furthering the economic improvement goals of ITS should be rated highly.
Existing data Although human factors research from other applications may help resolve many issues associated with ATIS development, placing advanced ATIS technology in cars and trucks involves a number of unique issues. The most critical issues on the list are those for which no previous research exists and so studies that resolve questions that no existing data address should receive high ratings.
Guidelines The purpose of this project is to develop human factors design guidelines for ATIS, not to simply examine how driver behavior may change as a result of these systems. Therefore, studies/issues that directly address potential design alternatives and would support designers' data base of human limits and abilities should receive high ratings.
Older drivers Older drivers present a particular challenge to ATIS design. They have special needs and limits that if addressed will help ensure a flexible system that can be adjusted to meet the special needs of a variety of populations. Because of the need to devote special attention to the needs of older drivers, studies particularly well suited should receive high ratings.
Younger drivers Younger drivers have highest accident rates and so special attention should be paid to enhancing their safety through ATIS designs.

 

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FHWA-RD-96-177

 

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