Seniors Cautious about Life in the Fast Lane

Slide behind the wheel of Dr. David Kaber’s baby, punch the gas, and watch the trees and buildings zip by. Just look out for a sudden collision that blocks an intersection or a construction project that closes a lane without warning. Plenty of people have experienced such road hazards without ever leaving Kaber’s lab in Daniels Hall. A professor in the Fitts Department of Industrial and Systems Engineering, he uses a high-fidelity simulator to measure people’s driving performance under various conditions. “With computer-generated graphics, we can control any event in the simulator,” he says. “It’s a safe way to look at performance in hazardous situations.”

“Older drivers compensate for their physical limitations with more mature behavior.”

A recent project compared the driving abilities of older and younger drivers on a city street with plenty of traffic, signage, and pedestrians, as well as on scenic, open roads in the country. Graduate student Yu Zhang, who designed the different scenarios, helps each driver get a feel for the simulator, which handles like a Taurus despite its Jaguar-like price. Three high-definition, wide-screen displays serve as the windshield and windows, with insets for the rear-view and side mirrors. Drivers in the simulator wear a head-mounted eye-tracker that uses infrared beams to monitor the direction of their gaze and how long they stare at certain objects. A “passenger” also sits nearby to ask questions about vehicle speed and events in the simulation so Zhang can gauge a driver’s awareness of the changing roadway situation.

The study found that drivers ages 65 to 81 have more trouble negotiating dynamic hazards, such as two cars colliding in front of them. Meanwhile, drivers ages 18 to 25 are more susceptible to problems with static hazards like construction barriers. Kaber attributes the former to age-related declines in mental and physical reaction time and the latter to younger drivers’ inattention. Older drivers also appear to have more difficulty with the “clutter” of an urban setting, he says, noting they tend to get tunnel vision and focus on what’s in front of them. “The data show some degradation of cognitive skills with age that impacts driving,” Kaber says. “That suggests older drivers might benefit from more frequent testing of their skills.”

Nonetheless, older drivers do demonstrate their experience in handling hazardous conditions, Kaber says. They control their speed and drive more cautiously as the complexity of the situation increases or if they have encountered an accident or construction zone. “Unlike younger drivers, who don’t readily adjust their behavior,” he says, “older drivers compensate for their physical limitations with more mature behavior.”

 

A high-fidelity simulator in Daniels Hall measures driving performance under various conditions, while a head-mounted device tracks the eye movements of test subjects.

Dr. David Kaber, left, and graduate student Yu Zhang, right, check a test subject’s awareness of changing roadway conditions during a driving simulation.