A video showing a man approaching a vehicle near Montreal and revving a chainsaw is one of a growing number of incidents revealing driver anger that have been posted on social media in Canada recently. But it's difficult to tell if road rage is on the rise — or if it's just attracting more online attention.

Karine Cyr told CBC News that the incident caught on camera in St-Jerome began when her husband followed a vehicle to get the licence plate number after they were cut off by an erratic driver.

The video of the incident was viewed more than 1.3 million times on Facebook in a matter of days.

Another video posted to Facebook recently showed a car stopping in front of another vehicle on a street in Fredericton. The driver walked back to the other vehicle to rant, saying that the man had cut him off. 

In February, a dash cam captured a driver getting out of his vehicle in Vancouver traffic to punch another driver through the window. 

Each of the incidents that made it online recently occurred in an urban area, a factor that could fuel aggressive behaviour behind the wheel.

"I think that one of the reasons why you tend to have this higher level of vengeful behaviour is that in urban areas, you're never going to be with [the] car alongside you or ahead of you again," said David Wiesenthal, a psychology professor at York University in Toronto who studies driving stress.

Seeing more of it

But some observers question whether road rage is on the rise.

"I think just because people are documenting it more doesn't mean that that actually translates to an increase in road rage," said Darryl May, director of Kanetix.ca, an insurance comparison website.

'When people get into slow-moving traffic, we find that everyone's stress level goes up.' - David Wiesenthal

"But we are getting to see lots more of it."

When it comes to hard evidence, it's difficult to tell if road rage is on the rise because there isn't a specific charge for it.

Many road rage behaviours can be considered aggressive driving, which is one of the leading causes of death on Ontario highways, said OPP Sgt. Kerry Schmidt.

Aggressive driving can include tailgating, weaving in and out of traffic, cutting in front of a vehicle too closely and not obeying traffic laws.

In a 2012 survey from Kanetix.ca, nearly 80 per cent of Canadians admitted to aggressive behaviour on the road.

"We still see it all the time and people are just frustrated on the highways I guess and … taking it out on their fellow motorists," Schmidt said.

More congestion, more stress

While observers such as May question whether road rage is on the rise, others see factors that could contribute toward an increase.

Wiesenthal, who studies driving stress, said that roads are getting more congested and the commuter time is also increasing.

And that leads to more stress and possibly more aggressive driving, he said, adding that when people watch road rage videos, it could also act as an invitation to drive aggressively.

"We've seen that in other contexts … people are influenced by what they see," Wiesenthal said.

Regardless of whether there has been an increase in road rage, studies have shown that driving causes stress, a factor that could lead to aggressive behaviour.

"When people get into slow-moving traffic, we find that everyone's stress level goes up," said Wiesenthal.

However, people who are predisposed to stress will have a greater spike in tension than others when behind the wheel.

Areas of higher congestion will yield higher stress levels because drivers may feel they have no control over traffic.

Feeling helpless

"They feel helpless and they can't do anything about it. They may not have any alternative route to choose from," Wiesenthal said.

Carlo Ratti

Carlo Ratti says measuring driving stress is the first step to reducing it. (Lars Kruger)

 A 2013 study from the Massachusetts Institute of Technology and Audi found that driving in chaotic city traffic can be almost as stressful as skydiving.

The study is a part of the Road Frustration Index, a project that aims to estimate the level of driver stress across the U.S.

"Intuitively we all understand that driving is stressful. However, measuring it can be the first step to reduce it," said MIT researcher and professor Carlo Ratti.

Audi is using the results of the project to develop ways to ease driving stresses, Ratti said.

If an individual's aggressive driving is caused by stress, Wiesenthal suggests listening to some favourite music. It's been shown to reduce stress compared to having no music in the vehicle. He said deep breathing exercises are also effective.

Insurance incentives

Apart from stress reduction techniques, May said that insurance programs that recognize good driving habits could act as an incentive to stop driving aggressively.

Telematic devices installed in vehicles or on smartphones can record driving information and send data to a driver's insurance provider. Drivers could get cheaper rates if their data shows good driving habits, May said.

"Everyone thinks they're a good driver, so they think they're going to get discounts, but if they don't get discounts, it's also a learning experience."

For those who don't want their driving data sent to insurance providers, a smartphone app called DriveSmart by Kanetix.ca will also detect aggressive driving.

The app automatically recognizes when a driver starts a trip and scores on acceleration, braking and handling.

"It will actually tell you how you're driving and give you a score and you can work on improving it," May said.