Aeronautical charts are full of symbols, lines, text, and other fine visual details. Pilots use the data on these charts every day to fly routes all over the world. These charts are also important tools to researchers who want to understand how people see and process visual information.
Maura Lohrenz, acting director of Safety Management and Human Factors at Volpe, manages research teams studying human factors issues related to aviation displays and technology. Lohrenz knows the value of applying new and evolving tools to better understand the implications that human factors has on safety.
Lohrenz was recently awarded a U.S. patent for an eye-tracking tool that she helped develop before joining Volpe. This tool analyzes multiple participants’ eye movements over a visual display, tracking where each person’s eyes look and for how long, and analyzing these data across participants. The results help to determine which features or events attract more attention and could be most distracting.
Developing an Eye-Tracking Patent
Lohrenz and her team asked a group of college students to search visually cluttered aeronautical charts for obstacle markers and recorded how quickly they found the markers. Students who visually dwelled on large sections of the charts while simultaneously gathering information presented in their peripheral vision could locate the markers faster than students whose eyes darted around the map quickly, but without dwelling on any area for long.
Tracking the eye movements of a test subject searching an aeronautical chart for a target. Areas the subject fixated on are denoted by blue circles, with larger circles indicating a greater duration of fixation.
Lohrenz’s team later repeated the study with experienced U.S. Navy pilots, who use these types of charts all the time. The findings among the pilots were similar: those who looked at information slowly and methodically were more successful at correctly identifying the obstacle markers.
“Most of the patented work in eye-tracking has only looked at one person at a time, and what we wanted to do was to collect multiple people's eye movements and use that to figure out what might be the most interesting information for most people,” Lohrenz said.
By recording and analyzing many observers' eye movements, researchers can determine what feature or event is typically seen first, the average time people focus on a feature or event, and whether some people (for example, younger or older people) are more or less distracted by certain features and events.
Application to Transportation Safety
Anyone operating a vehicle has to juggle information and use different visual displays. For example, drivers monitor their speed on the car speedometer while also looking out the windshield for road obstacles and traffic. Drivers may perform so-called secondary tasks that are not crucial to safety, such as tuning their radios or interacting with their GPS.
To keep roads safe, it is vital for researchers to understand which vehicle interfaces are distracting and how long drivers spend glancing away from the road.
In an F-18, there is a large amount of visual information competing for the pilot’s attention, so it is important that the cockpit is designed so that there is not unnecessary information, and that pilots are trained to direct their attention in the most strategic manner.
“One area we are interested in is operator distraction,” Lohrenz said, noting that her eye-tracking patent has applications to her current team’s research and project work at Volpe. “People are distracted by all kinds of stuff, such as their phone or something else in their car. We can track people’s eye movements while they are operating one of our simulators to try and understand how our participants do or don’t respond to an event in the simulation. That can be used to further transportation research.”
Several completed studies at Volpe have used eye and gaze tracking technologies. However, in the past, it could be time consuming for researchers to analyze that data, since only one participant could be analyzed at a time. For example, one study performed in the train simulator at Volpe looked at whether adding one new display to the rail environment would increase operator distraction. Data from each participant took around 14 hours to analyze. However, Lohrenz’s newly patented tool would make it possible to analyze all participants’ eye-tracking data together, saving considerable time and resources.
The potential uses of eye-tracking technology go beyond gaining insights into operator distraction.
“Eye-tracking has the potential to help us better understand driver impairment more broadly—not just distraction, but impairment as a result of fatigue, drugs, or alcohol,” Lohrenz said. “And we are not limited to driving—eye-tracking technology is applicable across all modes, like aviation and rail. We have a lot to learn from identifying what people are paying attention to.”