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Winter 2001

Research examines skills of elderly drivers

Photo of Herb Pick

Herb Pick

As people continue living longer, those aged 65 and older are becoming a growing segment of the population. By the year 2020, this group will account for approximately 20 percent of the driving-age population. Unfortunately, these drivers are already overly represented in the number of crashes per mile driven, and researchers want to know why. According to Professor Herb Pick of the University of Minnesota's Center for Cognitive Sciences, little research involving elderly drivers has been done on the main function of driving--that is, getting from place to place--and the attendant issues of spatial orientation and navigation.

So Pick, co-principal investigators Celia Gershenson and Marian Heinrichs, and graduate students Chryle Elieff, Elizabeth Jansen, and Selma de Ridder are studying the extent to which people have problems with orientation and navigation as well as why the problems occur and how they may change with age. The researchers recently surveyed a group of study participants, ages 25 to 65, about their travel route planning, their ability to stay on course and oriented to their surroundings during travel, and their methods of coping when lost or disoriented. In the preliminary findings, elderly drivers report experiencing more distress when lost, while younger and middle age drivers report experiencing frustration and anger. Also, the latter group will sometimes continue driving with the hope of sighting something familiar, while elderly drivers rarely do.

Next, the researchers used actual on-the-road and simulated driving tests to study how quickly participants could learn an unfamiliar route as well as what details they pay attention to along the route in order to learn it. The goal was to find out if the drivers learned anything more about the area surrounding the route$mdash;such as general spatial knowledge of the layout of the area—than simply how to follow the route.

The on-the-road driving test consisted of teaching participants a loop-like route through a suburban environment until they had learned it well enough to drive it without error and without prompting by an accompanying experimenter. As they drove the route, the participants' attention was called to a number of key landmarks and intersections. Once they had learned the route, the participants were asked to drive it again, but this time they were directed to stop at two different locations and aim a pointer toward out-of-view landmarks and intersections. The basic data—the participants' pointing errors, measured in degrees—comprised a performance measure that was compared for both the young and the elderly drivers.

The research team found that the young drivers' performance in localizing the intersections and landmarks was substantially better than that of the elderly drivers by approximately 15 degrees for both situations. This difference is statistically significant, the team says.

Photo of driver's view of simulated roadway

Driver's view of simulated roadway

The simulated driving test used a similar route, but the aiming task was restricted to intersections. When the performance of young and old drivers was compared, the performance of young drivers was again better than that of elderly drivers. The correlation between performance of the on-the-road and simulated driving tasks across all participants' performance was 0.82.

The similar pattern of results obtained in the real driving situation and in the simulator bodes well for future study, say the researchers, because the simulator allows them to better control the driving environment and subsequently achieve better standardization of conditions across participants. On the other hand, the simulator allows the researchers to manipulate variables (traffic, visibility, landmarks, etc.) that may effect a driver's orientation.

Since the results of the driving tasks suggest that acquiring and maintaining spatial orientation is more problematic for elderly than for young drivers, the researchers think it may be beneficial to develop procedures and techniques to help drivers with poor orientation skills and spatial knowledge to improve their driving performance. For example, Pick says they may find that younger drivers are better able than older drivers to keep track of the position of landmarks that have disappeared from sight, and that this skill is particularly useful for maintaining orientation. Research can then investigate how to train older drivers to maintain this skill or learn it from scratch.

Pick feels that the ability to train elderly drivers in this way will help them retain a greater sense of self-reliance and mobility, contributing to fewer driving accidents and a longer, better quality of life. Also, learning how humans use their sensing and perception processes to navigate may lead to methods for maintaining or improving these processes as they degrade with age or to technologies for augmenting or replacing those human capabilities.

The last phase of this research will study participants' sensitivity to orientation-related sensory information by asking them to judge how far they have turned using visual, biomechanical, and vestibular (inner ear) sources of information.