Human Factors Research

Volpe Center subject pilot wearing head mounted eye-tracking device to record where the pilot is looking during human factors experiments. In the airplane, eye-tracking data has been central in the evaluation of the usability of airport surface markings, of moving map displays in flight, and while on the airport surface as well as in investigations of aircraft lighting as seen from final approach. (Photo by Andrew Kendra)

Making Transportation Solutions Personal

Human error is currently thought to contribute to between 60 and 80 percent of all transportation accidents. As a result, one of the greatest challenges in transportation is to design technology and procedures that reduce the probability of such error by taking human behavior and capability into account. As new technologies are introduced in the transportation enterprise, increased complexity places additional demands on individuals and fundamentally changes the role of those who work in these environments. This evolving role, as well as the human-system relationship, must be analyzed, understood, and acted upon.

This issue of Highlights presents an overview of the Volpe Center’s Human Factors Division. Researchers in this Division analyze the relationship between human capability, behavior, transportation safety, and productivity using a systems approach. New developments in knowledge and procedures are successfully transferred across transportation modes to resolve a range of problems. The Division has a unique, multimodal perspective due to its long-term support of all the administrations within the Department of Transportation (DOT).

Long-Term Experience in Human Factors Research

The Volpe Center has supported DOT in human factors research since its inception, and became a formal division in 1983. At that time, policymakers began to realize that not all national transportation problems could be solved through the hard sciences and engineering, alone; other disciplines were required, such as economics, environmental research, social sciences, psychology, information technology, operational analysis, and strategic planning, all of which can be linked with human factors. The Center continues to develop expertise in human factors, migrating toward a human systems integration framework in which users’ requirements will be considered from project outset.

The combined experience of the Volpe Center’s human factors research team amounts to several hundred years, and the team includes highly qualified experts who possess depth of experience in engineering psychology, industrial engineering, organizational development, operations research, and information technology. This broad range of expertise allows for creative team building—within the Division, across the Center, and with our project sponsors—to provide insights to help solve transportation problems.

Crossmodal Experience

The Human Factors Division executes projects for all DOT modes; its knowledge base permits efficiency in operation by leveraging ideas from one program or mode to another. Working with other experts, at the Volpe Center and elsewhere, its researchers are able to identify human factors issues early in the development cycle. They pinpoint areas in which their seminal work in one transportation mode is relevant to other modes and champion a human-systems integration approach. Following are examples of the division’s cross-cutting research.

Information Communication and Display

Several Volpe Center projects address human factors considerations in the design and evaluation of communications and display technologies for aviation and rail operations.

Aviation: Electronic Flight Bags

Instead of traditional flight bags loaded with paper documents—such as checklists, operating manuals, and navigation publications—many pilots now use Electronic Flight Bags (EFBs), which may be installed on portable computers. EFBs are in use by a large number of corporate and private aircraft pilots as well as by several airlines. They are standard on new aircraft built by manufacturers such as Boeing and Airbus.

Since 1999, the Volpe Center has worked with FAA and industry to:

• Improve the safety of EFBs by identifying human factors considerations for their design and evaluation
• Help streamline and standardize EFB assessments
• Coordinate information about industry and policy trends related to EFBs

The Volpe Center’s research on EFBs has been referenced by FAA in various, widely used guidance documents. This research has also contributed to the development of international guidance. As a result, the Volpe Center hasmade a significant impact on the whole EFB-user community.

Integrated Vehicle-Based Safety Systems Evaluation

Schematic showing the coverage provided by lateral sensors on trucks to detect lane change threats. The Volpe Center is evaluating this technology as part of the IVBSS initiative.

The Integrated Vehicle-Based Safety Systems (IVBSS) initiative is a safety research program, sponsored by DOT and aimed at accelerating the introduction of integrated crash-warning systems in vehicles. These warning systems will assist drivers and reduce the number and severity of injuries resulting from rear-end, roadway departure, and lane-change crashes.

The Volpe Center is conducting an independent evaluation of IVBSS. This evaluation will include estimation of potential safety benefits, driver and fleet acceptance, and characterization of the integrated system capability. The Center’s human factors specialists provide technical support to determine driver and fleet acceptance. This work is being conducted in support of the Advanced Safety Technology Division.

High-Speed Rail: Automation in Locomotive Cabs

As the United States moves toward high-speed passenger rail service, questions have emerged regarding the appropriate configuration of automation in the locomotive cab. These questions are also relevant to freight and conventional passenger operations. Recent advances in technology hold the promise of achieving gains in safety and productivity through in-cab automation and minimal reliance on trackside infrastructure. However, FRA wants to better understand the implications of cab automation on human operator performance. By leveraging its previous experience with display automation for EFBs in aircraft cockpits [see above], Volpe Center researchers have been able to address automation issues related to locomotive cabs. The key questions are similar; for each mode, it must be determined which tasks are appropriate for humans to perform, which tasks are appropriate for computers, and which tasks should be shared. These determinations may have significant safety implications. Volpe Center researchers have emphasized the need for human-centered design of new technologies; that is, a technology should be designed on the basis of the needs and limitations of the operator rather than forcing the operator to adapt to the technology. FRA is placing its new simulator—the Cab Technology Integration Laboratory (CTIL)—at the Center’s Human Factors Laboratory in support of this effort.

The Volpe Center Human Factors Laboratory: Training Simulators

Train simulator at the Volpe Center human factors laboratory. The simulator is used to study human-factors problems in freight-railroad operations. (Photo by John K. Pollard)

The Volpe Center‘s on-site human factors laboratory, the Center for Human Factors Research in Transportation, operates partially under a Cooperative Research and Development Agreement with the Massachusetts Institute of Technology (MIT). The laboratory includes several research simulators aimed at replicating the experience of flying, driving, or operating as closely and realistically as needed to serve our sponsors. There are enough commonalities among the various simulator environments such that research topics, equipment programming, and data analysis in one transportation mode often have validity for simulator research in other modes. Facilities and equipment include a railroad dispatcher simulator, a high-fidelity locomotive simulator, three flight simulators, an electronic display development laboratory, an air-traffic-control communications laboratory, a sound attenuation room, and a navigation/workload room. In addition, there will be the new FRA modular technology simulator, and the Center has access to a Cessna 402B aircraft equipped for in-flight experimentation and eye tracking. For the FAA, Volpe Center researchers have developed a ground vehicle simulators for airport driver training to increase vehicle operator awareness of the measures required to prevent runway incursions by ground vehicles.

Human Factors Training Evaluation

Airline-Pilot Training and Evaluation: Simulator Fidelity

The Volpe Center is engaged in a long-term initiative to study the requirements for effective training simulators for FAA. In the 1990s, there was an effort to address the fact that accident rates for commuter airlines were higher than those for domestic commercial airlines. The “Commuter Rule,” which became final in 1995, required “one level of safety” for all airlines and included 17 safety recommendations. Recommendations for pilot training included providing access to simulators for all airlines and ensuring that simulator requirements added training value.

Lights on at Takeoff. Volpe Center researchers investigated how pilots were interpreting FAA advisory circular AC 120-74A-Flightcrew Procedures during Taxi Operations. One section of the circular advised flightcrews about procedures for the use of exterior aircraft lights to make the aircraft more conspicuous when taxiing into position for takeoff or taking off. Photograph shows a sampling of planes taking off. (Video capture by Andrew Kendra)

Early research showed that motion simulation of FAA-qualified simulators may be insufficient; the Notice of Proposed Rule Making for FAR Part 60 on flight simulator requirements contains stringent motion requirements. In response, the air transport community questioned whether added training value would result from the higher minimum requirements that were proposed. A key component of Volpe Center’s research included assessing whether motion is required for flight-simulator fidelity in air pilot training, focusing on the effect of platform motion on pilot training and evaluation. The research confirmed that motion is a factor, but concluded that pilots do not need to be trained on how to use motion cues. This result is contrary to popular belief but is supported by rigorous research. As a result, the Aviation Rule Making Committee (consisting of FAA and industry) removed the added motion specifications from its recommended final rule language for revising FAR Part 60.

This finding has the potential to save large amounts of money. For example, the Volpe Center’s research coincided with, and supported, the European commuter airplane manufacturer ATR’s decision to develop a fixed-base, high-level simulator with dynamic seat, intended for pilot licensing. This was done with the concurrence of the French government. ATR and others are pushing for consideration of such devices in the revision of the International Civil Aviation Organization’s flight simulator requirements document, which would greatly improve access to simulator training internationally. The Volpe Center is participating in this revision.

Safety Metrics in Human Factors Research

The importance of collecting data to quantify the effectiveness of safety measures is evident across the transportation enterprise.

Aviation Safety Performance Metrics

The Volpe Center provides international leadership in the area of aviation safety performance metrics. Measuring the performance of the system is critical for identifying areas of concern, developing mitigation strategies, and tracking progress. Volpe Center has been instrumental in developing strategies to measure the severity of adverse events on the ground (surface incidents) and in the air (airborne losses of standard separation).

An aircraft or ground vehicle that enters a runway without authorization can present a serious hazard to aircraft that are taking off or landing. Runway incursions have been responsible for several accidents and numerous serious incidents. Both FAA and the National Transportation Safety Board (NTSB) have identified the prevention of such incidents as among their highest priorities.

The Volpe Center supports FAA in several technical efforts to improve runway safety. In addition to supporting improvements in equipment provided to pilots and controllers, a key task is the ongoing analysis of runway safety data. Human factors specialists routinely analyze runway incursions and other surface incidents to:

• Identify areas in which error mitigation strategies are needed for pilots, controllers, airport vehicle drivers, and airport operators
• Develop strategies to reduce the frequency and severity of runway incursions
• Evaluate the effectiveness of error mitigation strategies

One measure of risk is the frequency and severity of adverse events. Therefore, one of the keys to runway safety is a reliable measurement of the severity of runway incursions. Volpe Center experts designed a tool, the Runway Incursion Severity Classification (RISC) model, to provide a consistent assessment of the outcome of runway incursions. The model is in the final stages of validation by FAA and is currently offered by the International Civil Aviation Organization (ICAO) to its member states.

Measuring the severity of an adverse event is also important when two airborne aircraft have less than the required separation. Volpe Center experts have revised the way the FAA classifies such events with respect to the severity of the outcome. While the previous FAA measure (the “Severity Index”) combined subjective and objective measures of both the outcome and the process that resulted in the event, the new metric is a purely objective measure of the outcome. This “Separation Conformance Metric” measures the severity of the outcome by comparing vertical and horizontal distance between the aircraft to the separation intervals required. While the absolute standards for required separation vary by environment, the separation conformance metric can be used in all radar environments, since the computation is the percentage of required separation that was maintained. The Separation Conformance Metric is now the official FAA measure for the outcome of losses of standard separation in the radar environments and is likely to be accepted as an international standard within the global aviation community.

Considering Human Factors Early in the Project Cycle

Transportation researchers have learned that it is critical to apply human factors principles and methods early in a project so as to obtain the greatest benefit. By teaming human factors specialists with engineers and potential system users, possible problems can be identified early, when they are easier and less costly to fix.

FAA Staffed Virtual Tower prototype. (Photo by Jonathan Lee)

FAA Staffed Virtual Tower (SVT)

Under the leadership of the Advanced Surveillance and Communications Division, Volpe Center researchers are supporting FAA’s NextGen program and have identified a need for developing and implementing staffed virtual towers (SVTs) for controlling air traffic at airports. In the future, air traffic control (ATC) services similar to those provided by existing control towers may originate from alternate locations, potentially away from the airport. The SVT concept utilizes two-dimensional displays of traffic information to eliminate the need for direct, out-the-window observation of aircraft. Benefits may include reduced capital investment in tower construction costs and retention of operational efficiency during poor visual conditions.

The Volpe Center produced a working prototype for managing terminal area air traffic based on existing tower display systems. The electronic systems that functionally replace the out-the-window view must be as accurate, reliable, and intuitive as the visual depiction currently available. Human factors specialists, working with a team of engineers and air traffic controllers, were able to incorporate human systems integration best practices in developing this prototype display. The resulting system was proven to be effective and easy to use in simulations, and controllers preferred it to the conventional tower cab view.

Driver Behavior at Grade Crossings

Traffic research vehicle for gathering information on vehicles approaching grade crossings; trailer design features solar charging batteries and secure tool storage. (Photo by Brian Gilleran, FRA)

Highway-rail grade crossings represent a significant portion of the overall risk from railroad operations, and the Volpe Center supports FRA in all aspects of grade crossing research, from technical to behavioral. Volpe Center researchers have worked to develop a more precise understanding of risks to highway and rail users at grade crossings and determine how best to decrease or eliminate various risk elements. It has been shown that a significant portion of gradecrossing collisions can be directly attributed to human behavior. Research on driver behavior at grade crossings and evaluation of measures designed to reduce risky behavior require fine-grained data regarding the timing of drivers’ decisions (to either brake or proceed through the crossing when a train is approaching).

For FRA, Volpe Center researchers from both the Rail and Transit System Division and the Human Factors Division are conducting an independent evaluation of a mobile, solar-powered device. The device gathers and automatically records the speed profile and size of each vehicle approaching a grade crossing during the interval immediately preceding and following the passage of a train through the crossing. This evaluation, which takes place early in this project cycle, combines the Center’s engineering expertise in evaluating technology with its expertise in human factors and provides a more robust data-gathering system.

Improving Operational Safety

Center human factors staff are also involved in analyzing operational safety and developing methods and tools to help operators better identify and manage human error.

Analyzing Close Calls

Reliable, accurate, and timely data are critical to safety improvement efforts. Safety data analysis enables researchers to identify and anticipate where safety problems may arise. Accidents are often preceded by “close calls,” which can act as warnings about unsafe conditions. Studying close calls can help in identifying safety hazards and developing solutions that prevent accidents. This proactive approach enables transportation safety specialists to better manage risk and save lives.

The Center’s work in this area for FRA demonstrates the value of implementing a reporting system that encourages employees to disclose safety-critical information. The Volpe Center is supporting FRA in the development, implementation, and evaluation of a first-of-its-kind confidential, voluntary system for reporting and analyzing close calls in the U.S. railroad industry—the Confidential Close Call Reporting System (C3RS). It requires a sense of trust by the employees who are required to submit reports. This system is being systematically measured and evaluated. Information that is collected will be shared with participating stakeholders to evaluate the effectiveness of the system for improving safety and managing risk. Developing the system required careful coordination with labor leaders, senior railroad managers, government management, and staff from different agencies. To date, several hundred events have been reported.

The system is helping FRA to meet its goal of significantly improving operational safety and was identified as an important element in the DOT Secretary’s Action List for 2007.

Human Factors Experts Guide Government, Industry, and the General Public

Volpe Center human factors researchers have been called upon to provide technical opinion and to deliver expert evidence to groups representing government, industry, and the general public. As impartial advisors, they can provide these groups with informed comments and explanations that, in turn, can help these entities to establish their own policies and determine a course of action.

Technology to Prevent Alcohol-Impaired Crashes

Alcohol-impaired drivers contribute to a substantial portion of crash fatalities and injuries. Recent advances in unobtrusive, miniaturized detection technologies offer the potential for vehicle-based monitoring of a motorist&rsuo;s blood alcohol concentration and driving performance, to detect signs of impairment and (if necessary) take action, such as preventing impaired drivers from starting a vehicle by disabling the ignition to prevent a crash.

NHTSA asked the Volpe Center to identify detection technologies and to assess their practicability and effectiveness. Conducting its examination on an international scale, Center researchers focused on technologies that seemed most promising in terms of feasibility, public acceptance, and issues pertaining to privacy and legality.

Center researchers have been called upon as specialists to make presentations at public forums. These have included a keynote presentation at the first meeting of the newly formed Blue Ribbon Panel for the Development of Advanced Alcohol Detection Technology (comprising leaders from NHTSA, the Insurance Institute for Highway Safety, and the automotive and insurance industries) and the annual meeting of the International Council on Alcohol, Drugs, and Traffic Safety (ICADTS). Center staff also helped prepare a presentation given by NHTSA to a Mothers Against Drunk Driving (MADD) symposium on anti-drunk driving technology.

Standards for Emergency Egress

Volpe Center researchers serve on Railway Safety Advisory committees that support the collaborative development of rail emergency evacuation regulations. The U.S. DOT Rollover Rig research and rescue training simulator, shown here, is designed to train emergency responders to deal with accidents, to enhance passenger rail safety, and to demonstrate the need for safety features. Here the rig is being used to develop and compare emergency lighting and egress signage alternatives. This photograph shows the difficulty of egression from a railcar following an accident. (Photo by John K. Pollard)

In a transportation emergency, it is often necessary to evacuate passengers and crew. Volpe Center experts have provided guidance to the transportation community on human factors and engineering considerations as they relate to the evacuation of trains, buses, and motorcoaches. Center staff members have provided extensive research support and recommendations to FRA’s Railroad Safety Advisory Committee (RSAC) Emergency Preparedness Task Force and the Passenger Systems and Electrical Committees of the American Public Transportation Association/Passenger Rail Equipment Safety Standards (APTA/PRESS) Task Force regarding standards for emergency lighting, emergency signs, and low-location exit path marking. As a result of the Wilmer, Texas, motorcoach fire that killed 23 nursing home residents being evacuated from Hurricane Rita, the NTSB recommended that NHTSA investigate human factors issues in the evacuation of buses and motorcoaches and recommend revisions to existing NHTSA regulations. NHTSA asked for Volpe Center’s support based on its experience working with FRA in studying passenger railcar emergency evacuation issues. This task is being performed by staff from the Rail and Transit Systems Division, the Structures and Dynamics Division, and the Human Factors Division.

The Future

The Center’s broad experience in human factors and transportation is evident from the examples given in this article. They reflect the ability to apply a systems approach to complex issues, utilizing various areas of human factors expertise and transferring and translating that information and experience from one mode or project to others. The Center has one of the largest, if not the largest, multi-modal staff of highly skilled transportation human factors specialists in the country. They have a strong commitment to understanding the ways people process information, make decisions, and function within the human and machine systems, and they are creative in applying this knowledge to get the job done well.

Volpe Center researchers are actively conceptualizing how to incorporate HSI into the Center’s developing work portfolio. Volpe Center human factors specialists have contributed to a National Research Council report, Human Systems Integration (HSI) in the System Development Process. This report examines the consequences of the disconnect between people and technology in the large-scale development process and the importance of considering human capabilities throughout the development process. It also describes the need for seamless integration of humans into the design process from various perspectives: human factors engineering, manpower, personnel, training, safety and health, and (in the military) habitability and survivability. The process known as human systems integration will provide guidance for system designers and developers and help prevent large-scale system accidents. The broad range of overall research activities that the Center conducts provides an opportunity to integrate the human factors viewpoint into many transportation research endeavors.