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This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-RD-98-178
Date: June 26, 1998

Identification of Human Factors Research Needs - Final Report



This report summarizes the activities and results of a preliminary human factors review for the Intelligent Vehicle Initiative (IVI) program. The IVI program is a major Intelligent Transportation Systems (ITS)-related program to address the advancement of introducing advanced technologies into a wide range of vehicle classes. "The primary goal of the IVI is, jointly with the motor vehicle and trucking industries, State and local DOT's, and other stakeholders, to accelerate the development, introduction, and commercialization of driver assistance products to reduce motor vehicle crashes and incidents. The IVI will emphasize the development of industry-wide architectures and standards, integrated system prototyping, and field test evaluations such that the government and industry participants can assess benefits, define the performance requirements, and accelerate the deployment of incremental driver assistance products."(1)

With the introduction of advanced technologies ranging from advanced collision avoidance systems (CAS) to comprehensive driver information systems, it is recognized that careful thought must be given as to how these systems interact with the human driver. Some work has been accomplished in this area, but much work remains to be done. This research performed by Battelle Memorial Institute provides a preliminary look at where additional human factors research might be needed to ensure that safe and useful IVI prototypes are developed.








(1) This information was extracted from the Statement of Work for the subject as developed by the U.S. Department of Transportation.



The Intelligent Transportation System (ITS) program continues to sustain momentum in the United States. Over the past 10 years, work has focused on identifying and testing advanced technologies that could improve the transportation systems in this country. Work has also focused on developing a National ITS Architecture that would allow deployment of a compatible infrastructure and standards that would result in nationwide compatibility. Much of the research done has focused on the vehicle. Significant advancements have been made in developing ITS systems that provide increased safety and convenience for drivers. For example, collision avoidance radar systems can detect objects in the vicinity of the vehicle. Smart cruise control systems are about to be introduced that continually look ahead of the vehicle and automatically maintain a safe headway distance. Route guidance systems are available with integrated maps that are aware of the detailed roadway network in a city to help the driver manipulate around problem areas caused by incidents or construction. Automated vehicle location (AVL) systems have been installed in public transit systems along with advanced scheduling algorithms to help transit operations provide reliable service to their customers. The possibilities are far reaching and the personality and functionality of our automobiles are changing.

However, there is a need to build several cars, trucks, buses, and emergency vehicles that include selected technologies for testing and demonstration purposes. It is essential to ensure that the technologies selected for inclusion on the vehicles are safe and engineered correctly. The vehicles will be used to test the interfaces to the human drivers, as well as all other systems in the vehicles. The vehicles will also be used to demonstrate to stakeholders the benefits that can be achieved. This work is being performed under the program title "Intelligent Vehicle Initiative" or IVI. This program has the primary objective of keeping the vehicles and associated vehicle technologies at pace with the other ITS work. The intent of the IVI is to improve significantly the safety and efficiency of motor vehicle operations by reducing the probability of motor vehicle crashes.

The IVI program is currently researching four classes of vehicles, including: (1) passenger vehicles, (2) commercial vehicles (i.e., trucks), (3) transit vehicles, and (4) specialty vehicles (i.e., fire trucks, ambulances, and police vehicles). The program has also introduced the concept of developing different generations of vehicles, each with more advanced technologies made possible by the experience gained from previous generations.

As part of the IVI program, the Federal Highway Administration (FHWA) funded a project with Battelle Memorial Institute, with significant support from ITS America,(1) to investigate the human factors issues for an IVI and identify human factors research needs that currently exist. The objective of the project was to help the United States Department of Transportation (U.S. DOT) identify human factors work that needs to be done early in the life cycle of the IVI program to ensure safe and well–engineered vehicles. This report summarizes the technical approach used and the results of this research.

Importance of Human Factors to the IVI

There are three distinct types of human factors integration that should be considered for the Generation I IVI: First, there is the integration that takes place between the driver–vehicle interface (DVI) components of a User Service (or User Services) and the DVI components of an existing vehicle. An example of this type of integration is the need to implement driver messages, display formats, and display locations for both the Real–Time Traffic and Traveler information system and existing displays in order to increase the usability and comprehension of the entire suite of in–vehicle displays and to avoid driver overload. Second, there are integration requirements between similar IVI User Services. For example, if an IVI vehicle is equipped with Rear–End, Lane–Change/Merge, and Intersection CAS, the controls and information displays associated with these devices must be integrated in a manner that supports rapid driver understanding and response when collision warning messages are presented. Third, there are integration requirements between different IVI User Services. For example, if an IVI vehicle is equipped with both an Obstacle/Pedestrian Detection CAS as well as a Routing/Navigation device, design issues such as display type and location as well as message priority, timing, and formats will be particularly important for the Generation I IVI.

The IVI has the potential to provide drivers with useful information on many driving conditions and situations; to improve driving performance; and, ultimately, to increase the mobility and safety of the entire driving public. The IVI clearly represents an increase in the number of displays and controls for the in–vehicle environment, with a concurrent increase in the amount and complexity of information presented to the driver. If human factors integration and design issues are not addressed throughout the development process for the Generation I IVI, there is a risk that this increase in information will lead to information overload, driver confusion, and actual decreases in driver performance and safety.

(1) ITS America provided significant support for facilitating a key workshop in the project and summarizing the workshop results. ITS America also provided valuable engineering support in execution of the program through the participation of Dr. Eddy Llaneras in all aspects of the project.





Safety on our highways is "Priority One" in the U.S. DOT. In recent years, significant gains have been made to improve safety, but opportunities exist to do more. These opportunities center around the IVI program. The IVI program is thought to provide the maximum public benefit at a reasonable cost and in the shortest time. The IVI program is a human–centered program that emphasizes the introduction of technologies that not only help drivers to achieve better control of their vehicles, but also provide convenience–type driver information in order to make traveling a more enjoyable and less stressful activity. To accomplish these IVI goals, interfaces between the driver and IVI systems are essential, whether the systems are included in the vehicle or in the supporting highway infrastructure. The Generation I IVI is expected to focus on in–vehicle technologies. However, the Generation II and III IVI's are expected to include more advanced technologies to better integrate the vehicles with the infrastructure components of our transportation system.

The strong emphasis on DVI components within the IVI calls for human factors involvement in all phases of IVI development. Attention to human factors issues will help ensure that information is presented clearly and in ways that elicit appropriate driver response. Much work has been done to study human factors issues of drivers, but this work focused on more traditional driver–vehicle interfaces. However, more human factors work is needed with the new technologies being introduced into a vehicle by the IVI. The primary objective of this project is to identify human factors research needs that must be addressed to ensure safe operation of an IVI. A secondary objective of the project is to solicit consensus among the stakeholders for an IVI to move the program forward in a coordinated and synergistic way.





This project was comprised of two major subtasks:

Subtask 1 provided for a Preliminary IVI Human Factors Technology Workshop to draw together the stakeholders in the IVI program to begin to define the technologies and the human factors issues that need to be considered in developing an IVI. Due to resource constraints, primary emphasis in the research focused on the Generation I vehicle. However, information generated in the research that encompassed more advanced generations of an IVI was documented in the project reports. The primary purpose of the workshop was to identify state–of–the–art technologies that can be applied to IVI vehicles; human factors issues with each technology; and, ultimately, the identification of human factors research needs. The workshop was also used to solicit input from the ITS community as a whole and to build consensus of the stakeholders as to what an IVI should be.

Subtask 2 investigated the preliminary infrastructure and human factors in–vehicle requirements for alternative configurations of an IVI. The data collected in the Human Factors Technology Workshop in subtask 1 served as a basis and starting point for the research performed to identify human factors research needs that exist. The results of the subtask 2 research are documented in this report.

The following information summarizes the work performed in each of the two subtasks as well as major conclusions derived from each. A more comprehensive summary of the conduct and results from subtask 1 is provided in the workshop proceedings published by ITS America (ITS America, 1997).





On December 10–11, 1997, an IVI Human Factors Technology Workshop was held in Troy, Michigan. The following objective statement was prepared to provide focused direction in organizing the meeting:

"The objective of the IVI Human Factors Technology Workshop is to provide invited transportation professionals the early opportunity to provide inputs to the development and establishment of human factors requirements for the Generation I intelligent vehicles. The workshop will be used to solicit input from stakeholders and build consensus. Vehicle classes to be addressed will include preliminarily cars and, to the lesser extent, buses, trucks, and emergency/special vehicles. Information to be discussed by the group will include:

  • Candidate in–vehicle technologies for inclusion and integration for a Generation I IVI vehicle.
  • The status of development and availabilityof each technology.
  • Functional descriptions and architecture requirements for the Generation I IVI vehicle.
  • Roadway infrastructure requirements to deploy the technology.
  • The human factors issues that need to be addressed for each identified technology.
  • Completed or ongoing research that has addressed identified human factors issues.
  • New human factors research that needs to be completed prior to introduction of the technology into an IVI vehicle.

The information will be used to determine needed human factors research needs for candidate technologies and systems. The information obtained from the workshop will also be used to document a set of requirements for supporting infrastructure, vehicle, and human factors research."

To accomplish the objectives defined for the workshop, the attendance was restricted to invitation only. Careful selection was done to include qualified stakeholders from the public and private sector as well as academia that would be impacted by an IVI program. Emphasis was also placed on selecting people who had a human factors perspective. The participation in the workshop was excellent, with more than 70 people attending.

The workshop began with several presentations to introduce participants to the subject topic and to raise some of the issues to be addressed during the 2–day session. The presentations, in order, were as follows:

  • Dr. Samuel Tignor (FHWA) and Dr. Duane Perrin (National Highway Traffic Safety Administration [NHTSA]) opened the workshop with presentations on the direction of the IVI program and how the Driver–Vehicle Interface (DVI) program related to the objectives of IVI.

  • Dr. Jeffrey Everson of Battelle provided an overview of international work that had been done to–date that was related to the U.S. IVI program. Dr. Everson's presentation included several examples of integrated, multi–functional vehicle prototypes incorporating active safety, navigation, and convenience systems that were contiguous with the 26 User Services identified in the U.S. DOT–published Request for Information (RFI).

  • Dr. Ian Noy of Transport Canada provided a presentation that stressed the importance of incorporating IVI considerations into an ITS development program such as the IVI to achieve "usable, suitable, and acceptable" systems. He discussed how human factors principles and research–based design can greatly enhance system safety by reducing human error. He emphasized the need to design and develop any IVI prototype from a system perspective as opposed to individual technologies.

  • Dr. John Campbell of Battelle presented the results of a survey that was sent to selected participants prior to the workshop. The survey was intended to provide a baseline for breakout group discussions by identifying the availability of the 26 User Services listed in the U.S. DOT RFI for a Generation I IVI, associated infrastructure requirements, and human factors research needs. Key survey findings presented included:

  1. Belief that most systems/User Services will be available for operational test rather than as commercial products (at least within the near term).
  2. Emphasis on navigation and collision avoidance services rather than convenience–based information systems.
  3. Evolution of infrastructure elements. Some concerns exist for completely autonomous systems (e.g., lengthy deployment lead times and system robustness).
  4. Emphasis on simpler and more narrow near–term solutions.
  5. A wide range of platform–independent human factors research needs.
  • The final presentation was given by Greg Barbato of the U.S. Air Force Research Laboratory at Wright Patterson Air Force Base. This presentation discussed some of the human factors–related lessons learned from a different, but similar, system development program (i.e., pilot crew system design program for a new aircraft cockpit). Barbato made the following three recommendations to the workshop participants:

  1. Identify the system requirements early in the development process.
  2. Understand the user population and how they think.
  3. Design/evaluate systems using a structured objective process such as a methodology used by the U.S. Air Force to design aircraft cockpits. He stated that the methodology could be adapted for automotive applications such as an IVI.

Following the introductory presentations, the participants were divided into six breakout groups. Each breakout group had a focus, but some groups focused on the same topics. Specifically, two groups addressed Collision Avoidance and two groups addressed Navigation Systems. Also, two groups addressed Information Systems, but one group focused on convenience–type systems, while the other focused on safety–type systems. Each group was asked to emphasize the work needed for light vehicles, but also to consider issues for heavy vehicles (i.e., commercial trucks), transit vehicles (i.e., buses), and specialty vehicles (i.e., ambulances). The groups were also requested to prioritize the Generation I vehicle, which was defined as a vehicle available in the next 4 to 5 years that could be controlled by the driver. The final instructions given to each breakout group were to develop human factors research statements that, in their combined opinion, were needed to deploy the functional areas being emphasized by their breakout group. Each group was asked to specify the following information for each research statement identified:

  1. Why the research needs to be performed.

  2. Key objectives of the research.

  3. General technical approach.

  4. Estimated period of performance.

  5. Estimated costs.

Each breakout group held two sessions during the workshop. The first session focused on defining the candidate functions to be included in an IVI and associated issues of each as an independent subsystem. The second session focused on the integration concerns that needed to be addressed when the candidate subsystems were combined in an IVI.

Summary of Research Statements Developed During the Workshop

A total of 48 research statements were developed during the 2–day workshop. Each contained a title, a reason why the research should be performed, key research objectives, a general technical approach, an estimated period of performance, and an estimated cost. Forty–three of these 48 research statements were described to the assembled workshop participants and rated with respect to perceived priority.

The research statements covered a broad range of human factors issues relevant to a near–term IVI. A preliminary review of the research statements and priority ratings provided by the workshop participants was conducted. Our review suggests that the majority of the research statements can be placed into one of four broad categories of human factors research needs. These four categories, along with the titles of the research statements from the workshop, are summarized below. More detailed descriptions of the research statements can be found in the proceedings developed for the workshop by ITS America (ITS America, 1997).

Identify the IVI's Implications for the Driver–Vehicle Interface (DVI). Many research statements focused on the need to examine critical interactions between the driver and the vehicle. For the most part, these research statements represented an expansion of traditional DVI issues to the new IVI.

Specific titles of research topics in this area were:

  • Investigate Haptic and Kinesthetic Warnings.
  • Driver Tolerance to System False/Nuisance Alarms.
  • Evaluation of Voice Recognition for IVI.
  • Define the Nature of the Human System Dialogue.
  • Define the Nature of the Adaptive Interface.
  • Information Display Assignment and Modality Assignment.
  • Requirements for Display Devices.
  • Basic Input Modality Research.
  • Methods for Comparing Workload in Different Conditions.
  • When Should the Navigation/Route Guidance Information System Be Interrupted, Turned Off, Superceded?
  • Voice Systems in the Vehicle for IVI.
  • Screen Size/Resolution.
  • Driver Condition Warning.

Characterize Baseline Driver Behavior and Develop Driver Models for IVI. A number of research statements identified the need to characterize baseline driving behavior across a range of driving situations and conditions. Another theme was the need to develop computational theories and models of driver behavior, and to use these tools to support IVI development. These are related and synergistic research needs, with the data obtained during studies of baseline driver behavior being used as input to the process of developing robust and useful driver models.

Specific titles of research topics in this area were:

  • Baseline Driver Behavior and Performance for Each Crash Type.
  • Relating Man–Machine Interface (MMI) Elements Quantitatively to Visual Demand Measures.
  • Acquisition of Driver Behavior/Driving Environment Data.
  • Integration and Development of Human Factors Driver Models for IVI.
  • The Driver as a Decisionmaker: Decisions and Decision Processes.
  • Describing Normative Driver Behavior Using Quantitative Models.
  • Driver Baseline for IVI.

Provide Industry With Human Factors Design Guidelines and Standards for IVI. The need to develop human factors guidelines and standards was identified as a high–priority research need by most of the breakout groups.

Specific titles of research topics in this area were:

  • CAS Warning/Alert Standardization.
  • Standardization of CAS Warning Criteria.
  • Guidelines of CAS Warning Type, Location, and Priority.
  • Prioritization of In–Vehicle Information Systems (IVIS) Message Delivery.
  • Standardization of Navigation Messages for IVI.
  • IVI Messages: How Much and How Often.
  • IVI Information Display Prioritization.

Determine the Feasibility and Optimum Design Approach for the Integration of IVIS Devices. A subset of research statements focused on the integration of multiple in–vehicle devices. Specifically, what are the human performance implications of having multiple (vs. single) sources of information for navigation and/or collision avoidance?

Specific titles of research topics in this area were:

  • Estimate Benefits of Stand–Alone and Integrated CAS.
  • IVI Integration and Multi–Task Performance: Effects on Driving Performance and Behavior.
  • Integration - IVI, Current Dash, and Roadside–Based Information.
  • IVI Field Infrastructure Requirements.
  • Integration of Navigation With Collision Warning, Collision Avoidance.
  • Comparative Feasibility of Unitary vs. Multiple Collision Warning Systems, All Systems.

Additional Research Topics. There were many additional research topics identified by the workshop participants. These included:

  • Driver Mental Model.
  • Field Test of Stand–Alone CAS Scheduled for Generation I Vehicles.
  • Contextual Assessment for System Optimization.
  • Establish Caution Levels for Infrastructure Road Traffic Database Static/Dynamic.
  • Loss of Skill and Negative Transfer.
  • IVI Market Research Evaluation.
  • Multi–Task Requirements of Driving: Attention, Perception, and Cognition.
  • Driving Condition/State Functional Constraints.
  • Defining Situational Awareness.
  • Driver Understanding of System Functioning.
  • Comparison of the Effectiveness of In–Vehicle Warnings to Extra–Vehicle Warnings.
  • Alternative Steering Control Devices as an Enabler of Information System Packaging Space.
  • How to Ensure Effective Driver Knowledge and Skill (Performance) Levels for Safe Operation and Use of Advanced, Information–Driven Vehicle Technologies.
  • Development of Experimental Methodologies for Assessing Risk Compensation Behaviors.
  • Build Prototype IVI Vehicles for Human Factors Research.

Workshop Summary and Conclusions

Dr. Sam Tignor and Dr. Duane Perrin provided the following general observations and conclusions for the IVI Human Factors Workshop.

IVI Program Direction:

  • Don't lose sight of the big picture.
  • Beware of technologies looking for an application.
  • Consider system feasibility vs. commercial viability. Systems must be acceptable to customers in all respects, including cost.
  • Place commercial vehicle applications ahead of those for passenger cars.
  • Develop an organized methodology for prioritization of projects. The scope of the program is potentially huge, encompassing an almost infinite number of possibilities (4 vehicle types, 26 User Services, 3 generations, various types of drivers, etc.). One potential criterion for prioritizing is benefits.

Benefits Estimation:

  • Consider both benefits and risks (both direct and indirect).
  • Consider more traditional alternatives. Hi–tech solutions may not be necessary or cost–effective.
  • Remember older vehicles.
  • Present situation is not the baseline; systems will need to interact in future environments (5 to 6 years) with more advanced cars and heavier traffic.
  • Benefits depend on driver acceptance. Acceptance depends on the driver's perception of benefits (perception does not necessarily equal reality).
  • Evaluation must consider behavioral adaptation effects.
  • Optimizing safety or efficiency at the individual vehicle level may not necessarily translate into greater safety and efficiency at the global level (risk migration).

Major Human Factors Research Needs:

  • Incorporate theoretical structures into system development and evaluation (need a method of ranking system "goodness").
  • Good understanding of baseline (normative driving behavior). Need to understand how drivers operate under different situations and conditions.
  • Measure overall net effect (long term, involving behavior adaptation).
  • Determine the feasibility of driver training.

General Conclusions:

  • Understand normal driver behavior (with and without systems).
  • Model driver mental decisions.
  • Apply scientific process to IVI design.
  • Don't use the "black box" approach. Consider how the system relates to other components (including the driver).
  • Understand integration issues. Electronic components (computers, stereos, televisions, etc.) work together only because thought was devoted to the issue upfront.
  • Consider the numerous research issues addressed by breakouts, including:

– Display location and types.
– Icon usage.
– System integration.
– Standards for system compatibility.
– Sensor fusion.
– Information prioritization.
– Estimates of benefits.
– False alarms.
– Training.





The objective of subtask 2 was to analyze the potential in–vehicle requirements and associated infrastructure needed to identify the human factors research needs that currently exist to develop an IVI. These human factors research needs can serve as a foundation for defining the human factors research that must be done to deploy safe IVI systems for the four platforms currently being considered.

To determine human factors research needed for any IVI platform requires definition of systems or subsystems that are to be incorporated in the IVI vehicle. Without a fairly precise definition of how IVI technologies will be implemented, resulting human factors research issues run the real risk of being vague and of little value. Identification of human factors research needs should reflect both the needs of individual technologies as well as the issues associated with the integration of multiple technologies. The systems and/or subsystems needed in any IVI configuration are determined by the User Services that are provided in the vehicle. The User Services considered in subtask 2 were defined by the RFI published by the U.S. DOT in December 1997.





There are four sections in this report: Introduction, Method, Results, and Conclusions. This section, the Introduction, provides a discussion of the purpose and objectives of this project and summarizes project activities to–date. The Method section describes the specific tasks and activities that have been performed by the project team in order to meet the project objectives and to provide useful and meaningful findings from this project. The Results section presents our results from subtask 2 of this effort. It includes a summary of each of the 26 IVI User Services and also presents 7 Technology Modules for the IVI, as well as 5 IVI Candidate Configurations. The results for Subtask 1 are presented in the Workshop Proceedings Report (ITS America, 1997). In keeping with the primary objective of this effort, human factors research needs are presented for each of the User Services, Technology Modules, and IVI Candidate Configurations. The Results section concludes with a summary and discussion of 15 human factors design issues that will be crucial to the successful development of the IVI. A Conclusions section summarizes the key findings from this effort, as well as the recommendations for future human factors research for the IVI. References are also provided at the end of this report.






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