TORONTO, ON — Quick: Do more accidents happen in lousy or good weather?

According to a new research study led by Sunnybrook Hospital physician and epidemiologist Dr. Donald Redelmeier, it’s actually the bright, sunny days that put us at greater risk. 

Redelmeier’s researchers examined the circumstances surrounding every road crash over the past 20 years that resulted in a patient arriving at the hospital for treatment. The researchers then cross-checked the weather at the time of the crash (along with a week before and after for reference).

According to the Sunnybrook website, of the 6,962 patients that were studied, the majority of life-threatening traffic crashes happened in the daytime. And the sunnier the day, the higher the risk. “The increased risk,” the study states,”was about 16%, and it was the same for drivers of all demographics, and wasn’t easily explained by glare at dawn or dusk. The same increased risk wasn’t found on days of cloudy or overcast weather.”

The study findings didn’t surprise Sharon Ramagnano, manager of trauma services at Sunnybrook.

“I think during the sunny summer days drivers may assume the road conditions are good and may drive faster,” she said. “There are also typically more people out on bright sunny days–more pedestrians, more cyclists, more motorcycles and more cars–and so drivers may be more distracted.”

“Don’t ruin a beautiful day with an ugly traffic crash,” Dr. Redelmeier said. “In particular, recognize that your judgment may be mistaken in bright sunlight and tempt you toward excess speeding. Check your speedometer and respect the police who enforce speed limits even when conditions are seemingly perfect.”