"Even minor aggression, such as swearing, yelling or making rude gestures, can increase the risk of a collision," said lead author Christine Wickens, scientist at Centre for Addiction and Mental Health (CAMH) -- a psychiatric hospital in Ontario, Canada.
Drivers who made threats, attempted or succeeded in damaging another car or hurting someone, had the highest odds of collision -- 78 per cent higher than those whose aggression was considered minor.
The risk is comparable to those who use cannabis and drive, Wickens said adding that it was striking how the risk of collision rose as the levels of aggression increased.
People who reported no driving-related aggression had the lowest odds of collision, with increasing risk among those who had minor aggression, and the highest risk of all among those who reported both minor and more serious aggression.
The strong association suggests these drivers may have a greater chance of a collision because they either drive more aggressively or are distracted by their anger from other hazards on the road, the study said.
"Reducing driver anger and aggression would potentially reduce the risk of collisions," Wickens suggested.
There are well established approaches to manage stress and anger, ranging from deep breathing techniques and listening to music to cognitive anger management programs. Leaving enough time on a car trip to reach your destination could also reduce stress, the researchers noted.
The findings were drawn from the CAMH Monitor, an ongoing survey of Ontario adults' mental health and risk behaviours, using responses from 12,830 people between 2002 and 2009.
Just under eight per cent of Ontarians reported having a car collision in 2015.
The group was analyzed in relation to their reported aggressive behaviour, while controlling for other factors that could increase the risk of collision such as age, sex, cannabis or alcohol use and other factors.
The results were published in the journal Transportation Research Part F: Traffic Psychology and Behaviour.
