Michelle Chan, a PhD student in the school's psychology department, put fellow students into a driving simulator and tested their skills behind the wheel.
The test was similar to playing a video game in a small, dark closet and asked subjects to drive down a computer-generated road as ads appeared with negative, positive and neutral words.
The negative words were the most distracting. Words such as "cancer," "war" and "abuse" caused most of the test drivers to slow down and veer outside their lane.
Some drivers also crashed into trees, other vehicles and pedestrians.
"Billboards are already distracting enough," said Chan. "But then when you add the negative emotional content, it adds on to the driving effects, so that can be detrimental to driving."
There have been many studies about distracted driving, but the 26-year-old believes she is the first to look at what she calls emotional distraction.
The study, recently published in the journal Accident Analysis and Prevention, examined the driving of 30 students on campus. Chan said results did not differ by age or gender, although test subjects with less driving experience were more easily distracted by the billboards.
Positive words — love, happy, excitement — also aroused test subjects. They tended to speed up even after they'd passed the billboards, although their driving was still more safe.
"With the positive (words), they actually drive pretty well," said Chan.
Chan said as soon as she gets a more high-tech driving simulator, she plans to study the emotional distraction of images on billboards. Graphic anti-smoking ads are one example.
"They tend to capture more attention, so drivers tend to look at them longer and pay less attention to the driving task."
Chan believes jurisdictions in Canada need to adopt rules that crack down on the content of billboards, similar to laws already in place in Australia.
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