It has been shown by studies that older drivers are less careful when driving on brightly illuminated highways at night.
Ryerson University researchers found that older drivers who rarely drove or avoided driving at night were less accurate and braked faster when they were driving with more light.
"This finding took us by surprise," said Maureen Reed, a Ryerson psychology professor specializing in vision science and lead author of the study, which was funded by the Ontario Ministry of Transportation.
During the study, researchers surveyed nighttime driving habits of 219 older adults 60 years and older. They also tested the visual and cognitive abilities of a second group of 97 adults, ranging from 19 to 84 years.
Finally, 75 drivers of that group took a road test in Ryerson's driving simulator lab to test their driving performance: first under light conditions typical of Ontario roads at night, then at a slightly brighter intensity.
The study showed that older drivers from the second group were able to see information signs and respond faster during the road simulation test when the highway was more brightly lit.
The survey data showed that many seniors often miss signs on roads while driving at night, which causes them problems in finding their way, among other traffic issues.
However, all drivers, including seniors, became less cautious under brighter road conditions.
They exceeded the speed limit and drove onto the shoulder of the highway more often. Older adults also were less accurate and precise in following road curves.
Reed suggests that older drivers may pay less attention to their driving under brighter driving conditions.
"In the lower light situation, they are slowing down and driving more carefully because they are having difficulty seeing objects and processing what's going on.
"With the higher light intensity, they felt they didn't need to be as attentive," he added.